Assigned Exercises: Block 4 Introduction to Statistical Inference 1. What are the assumptions underlying the use of parametric statistics? 2. For the following descriptive information: __ __ X1 = 36.8 X2 = 35.8 n = 157 t = 1.002 Provide the following: df = ______ p ____ .05 English Answer (Was there a significant difference?) __________ The remaining items relate to the following two research results: A. t = 2.445 B. t = -3.123 df = 98 df = 48 p < .05 p < .01 3. For which situation is the absolute magnitude of the difference greater? 4. For which situation is the power of the statistical tool greater? 5. In which situation is the probability of Type I error smaller? 6. Which of the two situations will “probably” have more clinical significance? 7. Assuming equal distribution of subjects to each of two groups, how many subjects were enrolled in Study A? _______ in Study B? _______ 8. What is the confidence interval associated with Study A? _____ Study B?_____ 9. What is the probability of error in rejecting the null hypothesis associated with Study A? _____ Study B? _____ Assigned Exercises: Block 5 Selection of Inferential Procedures: The Use of a Statistical Decision Tree Identify the appropriate statistical procedure for each of the following: 1. Children raised in single-parent families graduate from high school less frequently than children raised in “intact” families. 2. Stress, as measured by a 50 item questionnaire yielding a stress score, is higher among children living in urban settings than children living in rural settings or children living in suburban settings. 3. Acuity scores are good predictors of length of stay among ICU patients. 4. Women who smoke are more likely to have miscarriages than women who do not smoke. 5. Married post-MI patients have lower diastolic blood pressure than divorced or single post-MI patients. 6. VLDL blood values are good predictors of blood pressure and weight. 7. Class rankings of African-American students differ from class rankings of Asian students. 8. Physicians have higher incomes than nurses. 9. Age is a function of self-esteem, measured on an interval level scale, among adult diabetic patients. 10. There is an interaction between gender and room placement on patient satisfaction scores measured on an interval scale. (Note: this is a tricky one….if puzzled, check out “factorial designs” in the Block 1 reading.) 11. Height is a predictor of IQ among school-aged children. 12. Rank ordering on GRE scores is a good predictor of class rank at graduation among MSN students. 13. Nurse practitioners are less competent in interpreting research, as measured on a categorical continuum, than clinical specialists. 14. Nurses have more positive attitudes toward the elderly, as determined by a 25 item inventory, than physicians. Assigned Exercises for Block 6 Estimation and Measures of Difference Estimation of Population Parameters 1. In a ...

1. Assigned Exercises: Block 4
Introduction to Statistical Inference
1.
What are the assumptions underlying the use of parametric
statistics?
2.
For the following descriptive information:
__
__
X1 = 36.8
X2 = 35.8
n = 157
t = 1.002
Provide the following:
df = ______
p ____ .05

2. English Answer (Was there a significant difference?)
__________
The remaining items relate to the following two research
results:
A.
t = 2.445
B.
t = -3.123
df = 98
df = 48
p < .05
p < .01
3.
For which situation is the absolute magnitude of the difference
greater?
4.
For which situation is the power of the statistical tool greater?

3. 5.
In which situation is the probability of Type I error smaller?
6.
Which of the two situations will “probably” have more clinical
significance?
7.
Assuming equal distribution of subjects to each of two groups,
how many subjects were enrolled in Study A? _______ in
Study B? _______
8.
What is the confidence interval associated with Study A? _____
Study B?_____
9.
What is the probability of error in rejecting the null hypothesis
associated with Study A? _____ Study B? _____
Assigned Exercises: Block 5
Selection of Inferential Procedures: The Use of a Statistical
Decision Tree
Identify the appropriate statistical procedure for each of the
following:
1.
Children raised in single-parent families graduate from high
school less frequently than children raised in “intact” families.
2.
Stress, as measured by a 50 item questionnaire yielding a stress
score, is higher among children living in urban settings than
children living in rural settings or children living in suburban

4. settings.
3.
Acuity scores are good predictors of length of stay among ICU
patients.
4.
Women who smoke are more likely to have miscarriages than
women who do not smoke.
5.
Married post-MI patients have lower diastolic blood pressure
than divorced or single post-MI patients.
6.
VLDL blood values are good predictors of blood pressure and
weight.
7.
Class rankings of African-American students differ from class
rankings of Asian students.
8.
Physicians have higher incomes than nurses.
9.
Age is a function of self-esteem, measured on an interval level
scale, among adult diabetic patients.
10.
There is an interaction between gender and room placement on
patient satisfaction scores measured on an interval scale. (Note:
this is a tricky one….if puzzled, check out “factorial designs” in
the Block 1 reading.)
11.
Height is a predictor of IQ among school-aged children.

5. 12.
Rank ordering on GRE scores is a good predictor of class rank
at graduation among MSN students.
13.
Nurse practitioners are less competent in interpreting research,
as measured on a
categorical continuum, than clinical specialists.
14.
Nurses have more positive attitudes toward the elderly, as
determined by a 25 item inventory, than physicians.
Assigned Exercises for Block 6
Estimation and Measures of Difference
Estimation of Population Parameters
1.
In a research situation involving multiple measures relating to
burnout and employee turnover, a sample of 1,000 nurses was
assessed on their attitudes toward hospital administration. The
instrument used was an interval level device yielding scores
from 1 to 100, with 100 being the most positive. The mean
score of the group was 68 with a standard deviation of 12.5.
What is the best single estimate of the population mean (the
point estimate)?
What is the “standard estimate of the population mean?”

6. Assuming the need to be more confident, what is the interval
estimate of the population mean at the 95% confidence interval?
Comparing Samples to Populations: The z Statistic
2.
A nurse educator wants to know if her students’ scores on the
NCLEX are “higher” or “lower than the national average. Her
30 students averaged 869 on the NCLEX and she knows that the
national average is 850 with a standard deviation of 75. At the
95% confidence interval, are her students’ scores significantly
different from the national average?
Chi Squared (χ2) Test
3.
A nurse educator wishes to determine whether pre-licensure
education influences performance on certain advanced clinical
examinations. She acquires the ACLS (Advanced Cardiac Life
Support) data which indicate the pass/fail rates for 100
Associate Degree Nurses and 100 BSN Nurses. Sixty-eight
percent of the Associate Degree and 73% of the BSN nurses
passed the exam on the first attempt. Was there a significant
difference in the pass rates between the two groups?
4.
A nurse researcher wishes to know if attitudes toward HIV
positive patients differ among selected ethnic groups. She
identifies an instrument which yields categorical scores of
“positive,” “neutral,” and “negative” attitudes which she
administers to 30 white males, 30 Hispanic males and 30
African-American males. The African-American subjects were
evenly divided among the three categories, while among the
Hispanic men, only 5 indicated positive attitudes and 10
indicated neutral attitudes. The white subjects scored 15
positives and 10 negatives. Was there a significant difference
in the attitudes of these groups?

7. 5.
A clinical researcher wished to know if there were differences
in reported levels of pain between post-operative patients who
were given pre-operative teaching and those who were not.
Pain was reported on a nominal scale including 3 categories:
“Little or No Pain,” “Moderate Pain,” and “Severe Pain.” One
hundred subjects were randomly assigned, 50 to a group, to
“Teaching” and “No Teaching” conditions. Twenty-five of the
teaching and 20 of the no teaching subjects reported little or no
pain post-operatively. Twenty of the teaching subjects reported
moderate pain and 5 of the no teaching subjects reported
moderate pain. Was the teaching effective in helping to control
post-operative pain?
t-Test
6.
A nurse educator wants to know if self-paced instruction is
preferable to lecture-discussion as an instructional technique for
teaching students about the elderly. She divides her 100
students evenly and assigns them to one or another of the
conditions. She identifies an instrument which measures
knowledge of the elderly and administers the tool following the
instruction. Given the following data, was one technique
preferable to another at the .01 level of significance?
_
_
X1 = 58.5

8. X2 = 63.7
sd1 = 6.7
sd2 = 8.5
7.
In a study to determine the effect of pre-operative teaching on
patient satisfaction, 30 patients were given specific pre-
operative teaching before surgery. Another group of 20 patients
were not given the pre-operative instruction, but all 50 patients
were administered an interval level satisfaction instrument. At
the 95% confidence interval, was there a difference between the
groups based on the following data?
Teaching GroupControl Group
_
_
X = 23.5
X = 27.6
sd = 4.5
sd = 5.0

9. Analysis of Variance (the F ratio)
8.
A researcher is interested in the effect of specialty on burnout
among nurses. She selects subjects from three identified
specialty areas—critical care, pediatrics, and obstetrics. She
administers a valid and reliable measure of burnout which
yields interval scores from 0 to 100 where high scores indicate
high levels of burnout. Based on the following data, does
clinical specialty influence burnout?
PediatricsCritical CareObstetrics
n = 10
n = 10
n = 10
38
52
40
42
50
50

10. 40
60
45
45
55
40
44
62
50
36
65
48

11. 30
58
45
35
60
50
40
68
53
30
70
50

12. 9.
For the data in the problem above (# 8—burnout and clinical
specialty), answer the following:
a.
Which groups, if any, were significantly different?
b.
If you wished to compare each group to each of the other
groups, what would be required?
10.
In another study, patients undergoing three treatments for ESRD
were studied for life satisfaction. The outcome measure was a
tool yielding interval scores from 0 to 10, with 10 representing
the highest level of satisfaction. The three treatments were:
Kidney transplantation, center-based hemodialysis and
continuous ambulatory peritoneal dialysis (CAPD). Based on
the following data, are there significant differences among the
groups in terms of life satisfaction?
TransplantCenter-based HemoCAPD
n = 6
n = 6
n = 6
8

13. 5
7
8
6
5
9
3
6
7
6
5

14. 8
7
8
8
4
4
11.
The following ANOVA table was generated in a study to test
the following hypothesis: “Ethnic background significantly
influences biomechanical ability based on a 20 point scale.”
The study compared groups of students of different ethnic
backgrounds at a large Midwestern university.
Source
df
SS
MSS
F

15. p
Among
4
16833
4208.3
4.338
<.05
Within
245
237650
970
Total
249
254483
5178.3
a. How many groups were compared?

16. b. How many subjects were in each group (assuming equal
distribution)?
c.
The researcher concluded that biomechanical ability was
influenced by ethnic background. Do you agree with this
conclusion?
c. Based on this table alone, the researcher further concluded
that black students had higher biomechanical abilities than
oriental and white students. Is this conclusion justified? Why
or why not?
Assigned Exercises: Block 7
Correlation and Regression
Correlation: Pearson’s “r” and Spearman’s ρ (rho)
1.
A researcher wishes to know whether scores on a standardized
instrument (instrument A) are related to a shorted form of the
instrument (instrument B). To do this she selects 10 subjects
and administers both instruments. The following are the paired
observations. Determine the strength and direction of the
relationship and report its statistical and practical significance.
Subject #Instrument AInstrument B
1
84
42

17. 2
90
45
3
88
49
4
80
38
5
78
40
6
82
41
7

18. 85
41
8
79
36
9
75
38
10 100
49
2.
Another researcher wishes to know whether didactic rank is
related to clinical rank among nurses students enrolled in
clinical and didactic coursework. For twenty (20) students, the
following are the ranks given by didactic and clinical
instructors. Determine the strength and direction of the
relationship and report the statistical and practical significance
of the relationship.
Student #Didactic RankClinical Rank

19. 1
1
4
2
2.5
2
3
2.5
3
4
5
6
5

20. 5
6
6
5
6
7
7
1
8
9
10
9

21. 9
12
10
9
8
11
11
9
12
12.5
15
13

22. 12.5
11
14
14
15
15
15
13
16
16
17
17

23. 17
15
18
19
18
19
19
19.5
20
19
19.5
Regression
For the following data set of paired observations, perform the

24. identified statistical analyses and/or answer the questions
indicated:
xy
14
21
14
22
12
22
11
23
11
20
10
18

25. 9
17
9
21
8
15
7
12
3.
Calculate the correlation coefficient and report its statistical
significance.
4.
Report the percent of variance (the coefficient of determination)
shared between the known values for x and y.
5.
Using the linear regression equations provided, calculate and
report the slope of the regression line.
6.
Using the linear regression equations provided, calculate the y
intercept for the regression line.

26. 7.
Calculate the standard error of estimate for the regression
equations completed. (note: you’ll need to calculate the
standard deviation of y to complete this. If you’ve forgotten
how, review Block 3.
8.
Predict the value of “y” for a known value of x = 15.
As a point estimate:__________
As an interval estimate:___________
Assigned Exercises: Block 8
Interpreting SPSS (Statistical Package for the Social Sciences)
Output
This little exercise is based on your ability to interpret SPSS
output. In this instance, the exercise includes two pages of
questions that deal with a few pages of output that follow the
questions. The calculations performed include: Two (2) t-tests,
on (1) Chi-squared, one (1) F Ratio or Analysis of Variance
(Oneway ANOVA) and one Pearson r.
The first few questions deal with the output of the t-test. These
analyses compared men and women on two variables –the
number of children they had and their ages.
1.
Was the t-test the appropriate statistical device for these
comparisons?
2.

27. For the comparison of ages:
a. Report the appropriate test statistic.
b. Report the appropriate df.
c. Report the appropriate p value.
e.
Were there significant differences between men and women on
the variable of age?
3.
The “Crosstabs” output is the format for conduct a Chi-squared
analysis. In this case, different ethnic groups were compared on
a categorical measure of happiness.
a. Was the appropriate statistical test used?
b. What percent of white respondents reported being “very
happy?”
c. What percent of those reporting general happiness as “Not
Too Happy” were Black?
d. What is the appropriate test statistic for a comparison of the
groups?
e. What is the appropriate df?
f. What is the appropriate p value?
g. Was there a difference in general happiness according to
racial background?
4.

28. For the Oneway ANOVA:
a. How many groups were compared?
b. How many subjects were enrolled?
c.
Was there a difference among the groups
5.
The bivariate correlation examined the association between age
of the respondent and the highest year of school completed.
a. Was there a statistically significant correlation?
b. What was the percent of shared variance between age and
highest year of school completed?
c. In looking at the general trend, did older subjects tend to
have more years of school, or less years of school, than their
younger counterparts?