Biostatistics exam questions by tadele girum

Tadele Girum’s Biostatistics Exam question
WOLKITE UNIVERSITY COLLEGE OF MEDICINE AND HEALTH SCIENCES Page 1
WOLKITE UNIVERSITY
COLLEGE OF MEDICINE AND HEALTH SCIENCES
DEPARTMENT OF PUBLIC HEALTH
BASIC BIOSTATISTICS EXAM COLLECTION
Prepared by:
Mr. Tadele Girum (Bsc/PH, Mph/Epidemiology & Biostatistics)
Lecturer and Researcher
Address: girumtadele@yahoo.com;
tadele.girum@wku.edu.et ,
girumlijtade@gmail.com
Research gate, Linkedin, slideshare
address: tadele girum
Published researches: more than 14
Future shares: advanced biostatistics exam questions @slideshare
: Basic and advanced statistical analysis with SPSS and STATA video
(Survival analysis, time-series analysis, meta-analysis) @youtube, facebook & linkedin

Choose the best answer among the given alternatives
1. Which one is not appropriate for nominal data presentation?
A. Relative frequency table
B. Scatter plot
C. Pie chart
D. Bar graph
E. None
2. Which one of the following is not the merit of diagrammatic presentation against tables?
A. Shows trend
B. Greater attractiveness
C. Accuracy
D. Creates quick impression
E. None
3. The vertical line of a histogram represents:
A. Cumulative frequency
B. Relative cumulative frequency
C. True upper limit
D. Frequency
E. Mid-point of the class
4. Which one have the capacity to present a percentile
A. Frequency polygon
B. Pie chart
C. Ogive
D. Scatter plot
E. Line graph
5. Which one is not the future of mean?
A. Affected by extreme value
B. Each value determine the mean
C. used for nominal & continuous data
D. there is only one mean in a data
E. None
6. When mean, median and mode of a certain data set are not similar, the appropriate data
presentation is trough:
A. Median and quartile
B. Mean and standard deviation
C. Median and standard deviation
D. Mean and quartile
E. Mean and median
7. One of the following is nominal scale
A. Height of a mountain above sea level
B. Height of a man
C. weight of a stone
D. Color of a man
E. Number of students in your class
8. Which one is descriptive statistics
A. Generalization
B. Data collection
C. Inference
D. Hypothesis testing
E. Prediction
9. Which of the following measures of dispersion tends to be influenced only by largest &
smallest score?
A. median
B. mode
C. mean
D. range
E. variance
10. When mean, median and mode of a certain data set are similar, the appropriate data
presentation is trough:

A. Median and quartile
B. Mean and standard deviation
C. Median and standard deviation
D. Mean and quartile
E. Mean and median
11. Which one is not appropriate to present Ordinal data
A. Mode
B. Mean
C. Median
D. B&C
E. All
12. One of the following is interval scale
A. Height of a mountain above sea level
B. Height of a man
C. weight of a stone
D. Color of a man
E. Number of students in your class
13. During data collection the most valid information is obtained from
A. Face to face interview
B. Observation
C. Self-administered questioner
D. Focused group discussion
E. Repeated interview
14. Which one is not descriptive statistics
A. Generalization
B. Data collection
C. Data presentation
D. Data compilation
E. Summarizing
15. Four students has a median score 8 in this exam. If the highest score increases 2 points, the
median will become ____
A. 8
B. 8.5
C. 10
D. 8.2
E. Cannot be determined
16. If the mode, median and mean of a certain distribution are 7, 8, 9 respectively, then the
distribution is:
A. skewed negatively
B. not skewed
C. skewed positively
D. Symmetrical
E. bimodal
17. Which of the following measures of central tendency tends to be most influenced by an
extreme score?
A. median
B. mode
C. mean
D. range
E. variance
18. Let say, in your class with a total of 60 students; the mean result of biostatistics exam is 70
and the median result is 55. You will expect,
A. Many students have scored below the average
B. Many students have scored above the average
C. Half of students have scored above 70
D. Half of students have scored below 70
E. 65 students scored 70
19. The measure of central tendency which is sensitive to extreme scores on the higher or lower
end of a distribution is the:

A. Median
B. Mean
C. Mode
D. Range
E. all of the above
20. In a group of 12 scores, the largest score is increased by 36 points. What effect will this have
on the mean of the scores?
A. it will be increased by 12 points
B. it will remain unchanged
C. it will be increased by 3 points
D. it will increase by 36 points
E. There is no way of knowing exactly how many points the mean will be increased.
21. Among ten 2nd
year PH students, 3 students scored 4, 4 students scored 5, 2 students scored 9
and 1 student scored 10 in this exam. What is the mean of the scores?
A. 3.8
B. 6
C. 5
D. 4
E. 3
22. The following set of scores is obtained on Biostatistics test, X: 4, 6, 8, 9, 11, 13, 16, 24,
24, 24, 26. If the score 16 is corrected as 19. Which of the following indices will be
changed?
A. Median
B. Mode
C. Range
D. Standard deviation
E. All
23. The variance of a group of 10 scores in this class was 16. If 2 were subtracted from each
score, the variance of the new scores would be:
A. 14
B. 4
C. 16
D. 14.56
E. none of these
24. The scores that have the greatest effect on the value of the variance are those
A. Above the mean
B. Below the mean
C. Nearest the mean
D. Farthest from the mean
E. The mean it self
25. A percentile score of 60 indicates that a person
A. answered 60% of the questions correctly on the test;
B. knows 60% of the material covered by the examination;
C. has earned a score equal to or better than 60 persons in his class;
D. Has earned a score equal to or better than 60% of the persons in his class.
E. Has earned a score lower than 60% of the persons in his class
26. Alemitu obtained a score of 67 in a biostatistics test, placing her at the 84th percentile. If five
points were added to each student, her new score would be at the:
A. 89th
percentile
B. 84th
percentile
C. 72nd
percentile
D. 67.5th
percentile
E. Impossible to answer without
knowing others result
27. Let say HO & Medicine students took Biostat Exam together; if a score of 40 is at the 30th
percentile for HO and the 60th percentile for Medicines, which one is most likely true?
A. Medicine students generally performed better on the test than HO.

B. A person at the 15th percentile in HO will be at the 30th percentile in medicine.
C. A person at the 80th percentile in medicine will be at the 50th percentile in HO.
D. Medicine students generally scored lower on the test than HO.
E. None of the above.
28. In this test, Abe scored at the 87th percentile, and Kebe scored at the 73rd. This means
A. Abe is 14% better than Kebe
B. Abe scored 14 more points than Kebe
C. 14% of those taking the test got scores ranging between Abe's and Kebe's.
D. There were only 13 people smarter than both Abe and Kebe.
E. None of the above.
29. The mean of the population of ten scores, 78, 91, 91, 94, 74, 23, 63, 22, 78, 89 is 70.3, and
the modes are 78 and 91. The skewness of the population is:
A. Negative
B. Zero
C. Positive
D. not determined
E. Positive or negative depending on
the score.
30. What can we say about this graph?
A. is negatively skewed
B. Its mean is > the median
C. Its median is > the mode
D. It is symmetric
E. All are correct

I. Essay questions: compute the following
31. The following are the scores of 10 MLS students in this exam [3, 4, 5, 6, 7, 8, 8, 9, 10, 11]. If
40 percentile was the pass mark in this class, what is the minimum score a student should
score in order to pass the exam?
32. Compute and interpret mean, median and variance from the following frequency table
Table 1: A hypothetical data on total hours spent by PH students for this exam preparation, wku
Time
(Hrs)
Class
boundary
Mid-
point
Frequ
ency
Relative
frequency (%)
Cumulative
frequency
Cumulative relative
frequency (%)
10-14
15-19
20-24
25-29
30-34
35-39
9.5 – 14.5
14.5 – 19.5
19.5 – 24.5
24.5 – 29.5
29.5 – 34.5
34.5 - 39.5
12
17
22
27
32
37
7.5
12.5
25
30
15
10
Total 40 100

EXAM 2
A research indicated that rural children experience diarrhea roughly two times per year. Assume
that the time between episodes of diarrhea is normally distributed with a mean of 160 days and a
standard deviation of 40 days.
1. What is the probability of going 200 or more days between episodes of diarrhea?
A. 84.13%
B. 15.87%
C. 34.13%
D. 2.28%
2. What is the probability of getting diarrhea 80 days of a previous episode?
A. 2.28%
B. 97.72%
C. 5%
D. 15.87%
Assume that the score of biostatistics in your class is normally distributed with a mean of 74 and
a standard deviation of 10.
3. If you receive a score of 88. What percent of the class received scores higher than yours?
A. 91.92%
B. 14%
C. 8.08%
D. 1.4%
4. Suppose that Mr. Tadele wants to limit the number of „A‟ grades in the class to no more than
20%. What would be the lowest score for an A?
A. 17.6
B. 84
C. 78
D. 82.4
A research by Girum T etal.; Indicated that cases fatality (mortality) of malnourished
children in Dilla university referral hospital is 9.3%. If 5 malnourished children are
admitted,
5. What is the probability that 2 will die?
A. 7.15%
B. 99.3%
C. 6.45%
D. 0.661%
6. What is the probability that Fewer than 4 will recover/cure?
A. 99.96%
B. 7.15%
C. 99.99%
D. 0.034%
7. If two events are independent, then
A. they must be mutually exclusive B. the sum of their probabilities must be
equal to one

C. their intersection must be zero D. None of these alternatives is correct
8. Two events, A and B, are mutually exclusive and each has a nonzero probability. If event A
is known to occur, the probability of the occurrence of event B is
A. One
B. any positive value
C. zero
D. any value between 0 to 1
9. Which of the following is not property of a binomial experiment?
A. the experiment consists of a sequence of n identical trials
B. each outcome can be referred to as a success or a failure
C. the probabilities of the two outcomes can change from one trial to the next
D. the trials are independent
10. In a random sample of WKU students 50% indicated they are business majors, 40%
engineering majors, and 10% other majors. Of the business majors, 60% were females;
whereas, 30% of engineering majors were females. Finally, 80% of the other majors were
male. Given that a person is male, what is the probability that he is engineering major?
A. 0.28
B. 0.7
C. 0.5
D. 0.56
Assume blood-glucose levels in a population of adult women are normally distributed with
mean of 90 mg/dL and standard deviation 38 mg/dL.
11. Suppose the “abnormal range” were defined to be glucose levels outside of 1 standard
deviation of the mean, What percentage of individuals would be called “abnormal”
A. 5%
B. 2.5%
C. 32%
D. 95%
12. Suppose the abnormal range were defined to be glucose levels outside of 2 standard
deviations of the mean. What is the normal range of glucose levels (mg/dL)?
A. 52-128
B. 14-166
C. 85-95
D. 80-100
13. Suppose the score of biostatistics exam in public health students is normally distributed with
a mean of 64, and the standard deviation of 5. Among the following which interval includes
approximately 95% of the scores?
A. 63 to 65
B. 39 to 89
C. 54 to 74
D. 59 to 69
E. Cannot be determined

14. True about normal distribution curve
A. It is symmetrical bout its SD
B. The total area under the curve with in the 1SD is one square unit
C. The curve never touch the X-axis before 3SD but it does after 3sd
D. As the SD decreases the curve became narrower
E. All are correct
15. Let say, the score of 78% of students in this exam lie with in the 1 SD. Which one is true
A. It can‟t be 78%, because 1SD in normal curve contains only 68%
B. Their average score is very high, which exceeds 68%
C. The difference between students are minimal/low
D. Their mean score is minimum/low
E. The score is not normally distributed
Let say, you and your senior batches took the same exam on biostatistics; the score is
normally distributed with µ of 80 and σ of 5 for seniors and µ of 86.65 and σ of 5 for you.
Assume a student who scored above 90 is said to be “smart”
16. What percent of your batches were smart?
A. 25.14%
B. 2.28%
C. 74.86%
D. 77.2%
17. What percent of senior students were smart
A. 25.14%
B. 2.28%
C. 74.86%
D. 77.2%
18. Suppose in wolkite university a medical student have 90% chance to complete 2nd
year (the
1st
two years), whereas the chance that he survives to graduation(completing 7 years)is
60%.What is the chance that a person completed 2nd
year survives to date of graduation (on
7th
year)?
A. 33.3%
B. 1.5%
C. 66.7%
D. 30%
In public health department there are 12 male and 3 female lecturers. If you take 4 lecturers
randomly,
19. What is the probability that 3 are females?
A. 4.68%
B. 20%
C. 2.56%
D. 25%
20. What is the probability that 3 are males?

A. 41%
B. 59%
C. 2.56%
D. 25%
Fill in the blank space
In a random survey of grade 4 students, the average height was 146 cm, and the standard
deviation (SD) was 8 cm.
21. If a boy was 1.5 SDs below the average height. He was __________ cm tall.
22. What is the probability that a randomly selected student is between 142 and 150 cm tall?___
23. What is the probability that a randomly selected student is equal to or taller than 146 cm?___
Compute the following based on the given tables
Table 1: shows the frequency of khat/chat use by gender among adult users
Life time frequency of khat use Male Female Total
1-19 times 32 7 39
20-99 times 18 20 38
more than 100 times 25 9 34
Total 75 36 111
24. Given that the person has used khat less than 100 times, what is the probability of being
female?
25. What is the probability of a person randomly picked uses khat more than 100 times?
26. What is the probability of a person randomly picked is a male and uses khat more than 100
times?
Table 2: In malaria diagnosis the Gold standard method is assumed to be microscopy, there are
also other rapid tests as given below.
RDT Test Result Microscopy Result
Positive Negative Total
Positive 173 12 185
Negative 7 46 53
Total 180 58 238
27. What is the probability that a man does not have malaria has a negative RDT test?
28. What is the probability that a man does not have malaria has a positive RDT test?
29. What is the probability that a man with positive RDT test has malaria?

EXAM 3
1. Which assumption is wrong during sampling
A. Population with in strata are homogeneous
B. Population with in cluster are heterogeneous
C. The source population may be homogeneous or heterogeneous
D. The sample is a representative of the target population
E. None
2. Which one is wrong about a good sample
A. It is free from bias
B. It is the true representative of the population
C. It is comprehensive in nature
D. It have large sample size
E. None
3. In a single population proportion formula which component negatively affects the
sample size?
A. Margin of error
B. Confidence level
C. Odds ratio
D. Power
E. All
4. How could a sampling error be avoided?
A. It is not avoidable
B. By taking all populations as a sample
C. By taking large and representative sample
D. By designing the research with a good method
E. By standardizing data collection tool
5. In sampling distribution the values should be transformed to t-distribution in order to
know the probability in case of:
A. When population variance is unknown and not normally distributed
B. WHEN population variance is unknown but normally distributed or not
C. The population is normally distributed but the variance is unknown
D. The sample variance is unknown but the population variance is known
6. A national study was conducted; initially Region, Zones and woreda was selected, then
kebele followed. Within each selected kebeles 20 clusters (Got‟) containing 100 households
was demarcated. Lastly head of house hold with in selected clusters was interviewed. What
is the sample unit in this study?
A. Woreda
B. Got‟
C. House holds
D. Head of the house
7. Interval estimate is preferred than point estimates in that
A. It tells about variability
B. Shows the effect of sample size
C. It tells Precision of the estimate
D. All are correct
8. Which one is not true about student’s t-distribution
A. The total area in t-distribution is less than the z-distribution

B. It is less Bell Shaped than Z
C. The variability of a t is greater than that of a Z
D. there is more area under the tails
9. If the mean and standard deviation of serum iron values for healthy men are 120 and 15
micrograms per 100 ml, respectively, what is the probability that a random sample of 50
normal men will yield a mean of 125 micrograms per 100 ml or lower?
A. 0.9818
B. 0.9909
C. 0.0091
D. 0.99818
10. Let, 35 percent of WKU students are chat/khat users. What is the probability that in a sample
of 200 students drawn at random, 80 or more will use chat/khat?
A. 0.0694
B. 0.9306
C. 0.01388
D. 0.98612
11. The level of significance is the
A. The probability of rejecting a true H0
B. The probability of rejecting a true HA
C. the level of confidence coefficient
D. The probability of rejecting a false H0
12. In hypothesis testing, the hypothesis which will be true after the test is
A. the null hypothesis
B. the alternative hypothesis
C. the accepted one
D. the rejected one
10. In hypothesis testing, the hypothesis tentatively assumed to be true is
C. either the null or alternative
D. None
11. The level of significance is the
A. maximum allowable probability of Type II error
B. maximum allowable probability of Type I error
C. same as the confidence coefficient
D. same as the p-value
12. The probability of rejecting the null hypothesis when it is true is called:
A. Level of confidence
B. Level of significance
C. Power of the test
D. Type II error
13. The range of test statistic-Z is:
A. 0 to 1
B. -1 to +1
C. 1 unit
D. -∞ to +∞
14. Level of significance α lies between:
A. -1 and +1
B. 0 and 0.05
C. 0 and 1
D. -∞ to +∞
15. Test of hypothesis “could you score lower than 80 % in this exam?” leads to:
A. Left-tailed test
B. Right-tailed test
C. Two-tailed test
D. Difficult to tell
16. Smaller p-values indicate more evidence in support of:
C. the quality of the researcher

D. further testing
17. A passing student is failed by an examiner, it is an example of:
A. Type-I error
B. Type-II error
C. Unbiased decision
D. Power
18. Critical region is also called:
A. Acceptance region
B. Confidence region
C. Statistical region
D. Rejection region
19. The error which is introduced whenever we accept H0 is:
A. Type-I error
B. Type-II error
C. Level of confidence
D. power
20. The error which is introduced whenever we accept HA is:
A. Type-I error
B. Type-II error
C. Level of confidence
D. power
21. If the magnitude of calculated value of t is less than the tabulated value of t and the test
is two-sided, we should:
A. Reject Ho
B. Accept H1
C. Not reject H0
D. Difficult to tell
22. For a random sample of 9 women, the average resting pulse rate is x = 76 beats per
minute, and the sample standard deviation is 5. The standard error of the sample mean
is
A. 0.557
B. 0.745
C. 1.667
D. 2.778
23. A hypothesis test is done in which the alternative hypothesis is that more than 10% of a
population is left-handed. The p-value for the test is calculated to be 0.25. Which
statement is correct?
A. We can conclude that more than 10% of the population is left-handed.
B. We can conclude that more than 25% of the population is left-handed.
C. We can conclude that exactly 25% of the population is left-handed.
D. We cannot conclude that more than 10% of the population is left-handed.
24. Which of the following is true of the null and alternative hypotheses?
A. Exactly one hypothesis must be true
B. both hypotheses must be true
C. It is possible for both hypotheses to be true
D. It is possible for neither hypothesis to be true
25. The direction of a test statistics is determined by:
A. the alternative hypothesis
B. the null hypothesis
C. the analyst
D. the facts
26. A larger p-values indicate more evidence in support of:
C. the quality of the researcher
D. further testing
27. Sample size decrease as
A. level of significance increases
B. 2
increases
C. power increases
D. all
22. When testing a hypothesis at a 90% CI in two tailed test, HA is accepted if:
A. Calculated Z is < -1.645 B. Tabulated Z is >1.645

C. Calculated Z is > -1.645 D. Calculated Z is < 1.645
23. If 50% of exposed and unexposed individuals have developed the disease/outcome
A. RR=0
B. X2
=1
C. OR=0
D. No association
E. There is association but may or may
not be significant
24. A statistically significant association can be drawn from
A. OR=0.6(95%CI=0.1-1.09)
B. RR=1.1(P.value=0.04)
C. OR=1.7(95% CI=0.9-2.9)
D. RR=1.9(P.value=0.4)
E. A&D
25. A cohort of 400 smokers and 600 nonsmokers were followed for 10 years. During the
follow up 120 smokers and 30 of nonsmokers developed hypertension. The Risk of
hypertension among nonsmokers is
A. 6
B. 0.3
C. 0.05
D. 0.25
E. 0.15
Part II. True/false:
26. If we reject a null hypothesis about a population proportion p at the 0.025 level of
significance, then we must also reject it at the 0.05 level.
27. As number of observation increase t-distribution appears flatter.
28. Whenever we say α, it means p.value.
29. A wider confidence interval is more precise than the narrow one.
30. Whenever sample size increases confidence interval became narrow
31. When population are variable the sample size became larger
32. Randomization ensure the representativeness of a population
33. Hypothesis is about the population parameter/value while estimation is about the sample
34. In non-probability sampling there is no probability of selecting any individual
35. The observations (data) of the probability sample are used for the inferential purpose
36. Using the confidence interval when conducting a two-tailed test for the population proportion
p, we reject the null hypothesis if the hypothesized value for p falls inside the confidence
interval.
37. If we reject a null hypothesis about a population proportion p at the 0.025 level of
significance, then we must also reject it at the 0.05 level.
38. A Type II error is committed when we incorrectly accept an alternative hypothesis that is
false.
39. Sampling error can be avoided by taking larger sample size
Part III. Give short answer:
Match either “Z-transformation” or “T-transformation” is appropriate for sampling
distribution in the following scenarios
40. Population is normally distributed but the sample size is small and variance is unknown
41. The sample size is large, but population is not normally distributed and variance is unknown
42. Population is normally distributed & variance is known, but sample size is small
Calculate the confidence intervals in the following scenarios

43. Let, the mean score of 10 randomly selected 2nd
year MLS student is 85%. The class has 28
students and the variance of their score is 9%. What is the 90% CI for the mean score of the
class?
44. The mean weight of 16 students was 71.5 Kg with SD of 12 Kg. What is the 90% CI for the
µ?
For the following hypothesis use appropriate test statistics and decide whether Ho is
need to be “accepted” or “rejected”.
45. A simple random sample of 10 people from a certain population has a mean age of 27. Can
we conclude that the mean age of the population is not 30?Let 2
=20, α=.05.
46. In a survey of injection drug users in a large city, researchers found that 18 out of 423 were
HIV positive. We wish to know if we can conclude that fewer than 5% of the injection drug
users in the sampled population are HIV positive. Let α = 5%.
47. Please write the decision or the error which may be committed at each space
(Type I error, Type II error, Confidence level and power)
Truth Decision
Ho is not rejected Ho is rejected
Ho is true
Ho is false

EXAM 4
1. All are characteristics of scientific researches, except:
A. It is Parsimonious
B. It is Specific
C. It is haphazardly collected
D. It is Open for modification
E. It is empirically verifiable
13. Which condition necessitates a research?
A. Presence of discrepancy
B. Presence of more than one plausible answer for the problem
C. Presence of many solution to a problem
D. The reason for the discrepancy is unknown
E. All
14. Part of a research in which the researcher convinces the need for the research by explaining
the scope of the problem, discrepancy and its impact is:
A. Title/topic of the research
B. Objective of the research
C. Literature review
D. Statement of the problem
E. Design of the research
15. Which one is wrong about Qualitative data collection methods?
A. have deeper insight
B. demands researcher‟s direct
interaction
C. the sample size is smaller
D. aimed at drawing generalization
E. none
16. To determine whether noise affects the ability to solve math problems, a researcher has
assigned two groups to solve math problem one in quiet and another in noise rooms. The
group in the noisy room completes 15 problems in 1 hour and the group in the quiet room
completes 22 problems in 1 hrs. What is the independent and dependent variable respectively
A. The number of problems solves; the difficulty of the problems
B. The number of problems solved; the noise level in the room
C. The noise level in the room; the number of problems solved
D. The noise level in the room; the difficulty of the problems E. No variable at all
17. Which condition reduce the quality of a research
A. Randomization
B. Matching
C. Stratification
D. Blinding

E. Missing
18. Which one is wrong about a good sample
F. It is free from bias
G. It is the true representative of the
population
H. It is comprehensive in nature
I. It have large sample size
J. None
19. In which design representativeness of samples to the general population is a major concern
A. Case-control study
B. Cross-sectional study
C. Case-series
D. Correlational study
E. Case-report
20. In a single population proportion formula which component negatively affects the sample
size?
A. Confidence level
B. Margin of error
C. Odds ratio
D. Power
E. All
21. Which one is lacking in descriptive studies
A. Prevalence
B. Coverage
C. Frequency
D. Odds ratio
E. All are part of descriptive studies
22. Let say, a new drug “X” is developed to treat severe malaria. To study its effectiveness
randomly selected 200 malaria cases selected and given drug “X” for 60 and arthesunate for
the rest 140, the treatment outcome was recorded. In this case what is treatment outcome
A. Experimental Variable
B. Independent Variable
C. Dependent Variable
D. Controlled Variable
E. Case variable
23. Which one is wrong during study participant selection?
A. In a case-control study participants are selected in the basis of disease
B. In cohort study participants are selected on the basis of exposure
C. In experimental study participants are selected on basis of disease or un exposure
D. In cross-sectional survey participants are selected on basis of exposure or disease
E. None

24. Let say, 4th
year midwifery students developed vaccine for HIV. During the study 600 HIV
exposed neonates were selected and based on the mothers preference, the neonates were
given either the vaccine or placebo then followed for due time. What is the design of the
study?
A. Randomized controlled trial
B. Prospective cohort
C. Case-control
D. Quasi-experimental
E. Cross-sectional
25. One of 4th
year midwifery student conducted his undergraduate study on “prevalence of
hypertension among students”. In this case even though the instrument is digital,
standardized and calibrated and data collectors were trained; the fact that individuals have
biologically influenced to have different B/P measurement which introduce:
A. Sampling error
B. Bias
C. Non –random error
D. Measurement error
E. No error at all
26. A researcher wants to study the prevalence of fever among wolkite university students, which
data collection method is/are appropriate for him?
A. Interview with structured questioner
B. Interview with unstructured questioner
C. Participatory observation
D. Focused group discussion
E. All are appropriate if there is enough resource
27. A researcher wanted to determine the association between BCG vaccination and
Tuberculosis. Then he randomly selected 500 participants and asked their vaccination status
and tested their sputum with microscope. What is the design of the research?
A. Cross-sectional
B. Case-control
C. Cohort
D. Experimental
E. Quasi-experimental
28. The choice of study design for research is influenced by:
A. Particular features of the exposure and disease occurrence.
B. Logistic/ resource
C. Experience of researcher

D. Research Questions
E. All
29. The advantage of data collection from documentation/secondary source may be all, except:
A. It is cheap
B. It is good for retrospective data
C. It is incomplete
D. It is more reliable
E. None
30. A researcher wanted to determine the prevalence of low birth weight and asked mothers of
under five children the weight of their child at birth in which mothers may not remember:
what type of bias is introduced?
A. Recall bias
B. Observer bias
C. Interviewer bias
D. Measurement bias
E. No bias is introduced
31. Which one is not a component of methods/methodology in a proposal
A. Data processing
B. Hypothesis
C. Design
D. Eligibility criteria
E. Data collection procedure
32. Which one is ethically in-correct during conducting a research
A. respect the right to self-
determination
B. not to inflict evil
C. withhold a treatment
D. equal treatment/equality
E. paying for loss
33. What is the difference between research report writing and proposal writing
A. Report includes executive summery
B. Proposal includes abstract
C. Work plan is the last chapter in report writing
D. Conclusion is the last chapter in proposal
E. Methodology is written in past tens in report
34. Within the statistical association between “X” and “Y”,[ Adjusted odds ratio = 2.3, CI= .85-
4.6, p.value=0.4]; inevitably there is:
A. Chance
B. Confounder
C. Bias
D. All
E. Impossible to determine

33. To study the prevalence of hypertension among adults in wolkite town, 120 households were
randomly selected and the B/P of 120 adults dwelling in these houses was measured. In this
research the 120 households are:
a. Source population
b. Study unit
c. Study population
d. Sampling unit
34. Identify the wrong statement
a. In probability sampling all individuals always have equal chance to be included
b. In probability sampling inclusion to the sample is by chance
c. In probability sampling inclusion to the sample is by random
d. A&B
35. With the presence of group difference which technique is most appropriate for sampling
A. Simple random sampling
B. Stratified sampling
C. Systematic random sampling
D. Multistage sampling
36. Which one is not a non- probability sampling
a. Cluster sampling
b. Quota sampling
c. Purposive sampling
d. Convenience sampling
37. Identify the odd one
a. Bias b. Random error c. differential error
38. ---------- is Inaccuracy which is similar in comparison groups
a. Sampling error
b. Non sampling error
c. Precision
d. Validity
39. Sr. Hewan and Sr. Meron measured the weight of a 70kg man three times with the same
weight scale and found the following. Sr. Hewan= 65, 65, 65 kg Sr. Meron= 69, 71, 70 kg.
based on these which one is false:
a. The measurement of Sr. Hewan is reliable
b. The measurement of Sr. Meron is valid
c. There is no error in case of Sr. Meron
d. A&B
40. In single population proportion formula which prevalence/proportion gives the biggest
sample size, while W and CI kept constant
a. 50%
b. 90%
c. 25%
d. It depends on beta value
41. Which one is wrong about Qualitative data collection methods?
F. have deeper insight
G. the sample size is smaller
H. demands researcher‟s direct interaction
I. aimed at drawing generalization
42. During focused group discussion participants are recommended to be heterogeneous to get
different ideas.
a. True

b. False
43. From a research title “Determinants of Long Acting Contraceptive Utilization among
Married Women of Reproductive Age in Wolkite Town: A Case-Control Study” the specific
objective can be:
a. To determine the prevalence of long acting contraceptive use
b. To determine the incidence of long acting contraceptive use
c. To identify socio-demographic determinants of long acting contraceptive use
d. To assess the effect of long acting contraceptive use on maternal mortality
e. All are correct
44. Among the following study designs which one give more evidence of causal relation ship
a. Cohort study
b. Randomized control trial
c. Case control
d. Ecological study
e. Cross-sectional study
45. In which design the unit of analysis is a population rather than individuals:
a. Case-report
b. Case-control
c. Case-series
d. Correlational
e. Cohort
46. Experimental studies are different from observational studies in that:
a. Experimental studies have comparison groups but observational
b. Experimental studies randomly assign groups but observational
c. Experimental studies test hypothesis but observational
d. In Experimental studies unit of analysis is individuals but in observational
e. In Experimental studies researcher expose individuals but in observational
47. Identify the wrong statement
a. “Chicken and egg dilemma” is common in cohort study
b. Case-control study is appropriate for studying rare disease
c. cohort study is appropriate for studying rare exposure
d. case series is important to generate hypothesis
e. cross-sectional study can be analytical or descriptive
48. All are characteristics of scientific researches, except:
A. It is Parsimonious B. It is Specific

C. It is haphazardly collected
D. It is Open for modification
E. It is empirically verifiable
49. Identify the odd one
a. Applied research
b. fundamental research
c. action research
d. Operational research
50. Which condition necessitates a research?
A. Presence of discrepancy
B. Presence of more than one plausible answer for the problem
C. Presence of many solution to a problem
D. The reason for the discrepancy is unknown
E. All
51. Part of a research in which the researcher convinces the need for the research by explaining
the scope of the problem, discrepancy and its impact is:
A. Title/topic of the research
B. Objective of the research
C. Literature review
D. Statement of the problem
E. Design of the research
52. Which one is not the importance of literature review?
a. To Indicates why particular research project is needed
b. To reinventing the Wheel
c. To increases knowledge on the problem
d. To be familiar with different research methods
e. To prevents duplication
True or False
53. Qualitative researches are commonly involving measurements.
54. Researches conducted on the priority problem are more relevant.
55. Case serious studies are commonly important to test hypothesis
56. Cross-sectional studies are considered descriptive studies once they draw association
Part: III. Essay

1. A researcher wanted to measure event “X” among 3rd
year health science students of WKU.
He planned to take sample with systematic random sampling. With this intension he orderly
registered all health science students in a single order and given ID. The order is health
officer, midwifery and nursing students respectively. Given that HO students are 80,
midwifes are more than 50 and nurses are unknown (only the researcher knows). The first 3
selected students in HO class are: ID 7, 14 and 21. Based on this list the first 3 students in
midwifery class.
Please don’t forget to give me a comment!
Thank you very much!
October/2017

Biostatistics exam questions by tadele girum

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