This document contains a biology assignment with questions about statistical analysis, including defining statistical terms, interpreting graphs, and performing t-tests. The student is asked to cite sources using the CSE citation style. Questions cover topics like calculating mean and standard deviation, interpreting overlapping standard deviations on graphs, and determining whether differences between sample means are statistically significant based on t-test results and P-values. The student is also asked to self-assess their work.

1. Essential Biology Due Date:
Student Name: Candidate Number: 002171-xxx
Blog resource: http://tinyurl.com/25uz2zf
Cite all sources using the CSE method (or ISO 690 Numerical in Word). The first example has been done for you.
Complete the self-assessment rubric before submitting to Moodle. Avoid printing this if possible.
1. Define the following terms:
a. Mean: a measure of the central tendency of a set of data. (1)
b. Variability
c. Standard deviation
2. Errors bars show variability in data (either range of data or standard deviation)
State which two pairs of groups below can we see an overlap in the standard deviation of the
data.
a. And
b. And
c. In which group is the mean NOT likely to
be significantly different to the mean of
group 3?
-
Graph taken from http://www.csupomona.edu/~jcclark/classes/bio542l/essays/graphtypes.html
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2. Essential Biology Due Date:
Student Name: Candidate Number: 002171-xxx
3. On the axes below, plot the following three curves (all have a normal distribution):
a. Has the highest mean and a high standard deviation.
b. Has the lowest mean, but the highest frequency at that mean.
c. Has a mean between (a) and (b) and has the smallest standard deviation.
4. Complete the following paragraph:
± 1σ (standard deviation) from the mean represents ____ % of all the data points.
In data with a high standard deviation, data are clustered closer to/ further from the mean.
In data with a low standard deviation, data are clustered closer to/ further from the mean.
Overlapping standard deviations suggest two datasets are/are not significantly different.
___ % of all data fall within 2 standard deviations of the mean.
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3. Essential Biology Due Date:
Student Name: Candidate Number: 002171-xxx
6. Calculate the means and standard deviations of these two
Group A Group B
groups of data (to one decimal place)
24 24
25 29 Show your working here.
26 25
23 23
25 29
25 32
26 34
27 31
23 32
23 29
Mean
Stdev
P= 0.004 (T-Test)
7. In a t-test comparing Group A and Group B, the P value was calculated as 0.004.
What does this P value tell us about these two sets of data?
Explain your answer.
8. Why does the scientific community place so much importance on significance tests such as the t-test?
SKILLS CHECK I can calculate mean and standard deviation using:
a. A graphical display or scientific calculator
b. Microsoft Excel 2007
Stephen Taylor Bandung International School http://sciencevideos.wordpress.com

4. Essential Biology Due Date:
Student Name: Candidate Number: 002171-xxx
9. Use the t-table shown to perform the t-tests with
these examples. Make sure you follow conventions
and write everything down correctly each time (as in
part b).
a. Which confidence limit do we normally choose in
Biology? Why?
b. A student measures 15 snail shells on the north
side of an island and 16 on the south.
H0 =
Confidence =
DF =
Critical value =
t is calculated as 2.02.
So we reject/accept Ho.
Conclusion:
c. A student measures the resting heart rates of 10
swimmers and 12 non-swimmers.
t is calculated as 3.65.
So:
Conclusion:
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5. Essential Biology Due Date:
Student Name: Candidate Number: 002171-xxx
10. A researcher is investigating the link between air pollution and egg size in chaffinches. She measures
the diameters of eggs at 8 sites near a factory and 9 sites out of town. The mean egg diameter by the
factory was 5.6cm, whereas it was 7.4cm out of town.
t is calculated as 2.08
So:
Conclusion:
11. A doctor is testing the effectiveness of two kinds of antiseptics against bacterial cultures. He sets up
six samples with antibiotic 'A' and six with antibiotic 'B' and after 2 weeks counts the numbers of
bacteria present in each. Mean counts: A = 5.6x104cells; B = 5.7x104cells.
t is calculated as 1.97
So:
Conclusion:
12. A recent study looking into male fertility found that men who drank 3 cups of coffee a day showed
signs of more sperm tail damage (39.1% of sperm) than those who did not (32.8%). 22 men sampled
drank no coffee. 18 drank 3 or more cups a day.
t is calculated as 3.35
So:
Conclusion:
9. Look at the graph below:
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6. Essential Biology Due Date:
Student Name: Candidate Number: 002171-xxx
13. Identify the true statements, according to the graph:
a. There is no correlation between number of cellphones and number of students with asthma.
b. There is a positive correlation between number of cellphones and asthma cases.
c. There is a negative correlation between number of cellphones and asthma cases
d. Increased numbers of cellphones cause an increase in numbers of students with asthma.
e. Increased numbers of asthmatic cause increased numbers of cellphones in a school.
f. There is no evidence of causality in this graph.
14. Suggest two comparisons in which a causal relationship is likely
(e.g. temperature and rate of reaction).
a.
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7. Essential Biology Due Date:
Student Name: Candidate Number: 002171-xxx
Works Cited
1. Taylor, Stephen. Statistical Analysis (presentation). Science Video Resources. [Online] August 2010.
http://sciencevideos.wordpress.com/bis-ib-diploma-programme-biology/statistical-analysis/.
2. Allott, Andrew. IB Study Guide: Biology for the IB Diploma. s.l. : Oxford University Press, 2007. 978-0-
19-915143-1.
Self Assessment:
Essential Biology Assessment
Criterion Complete (2) Partially complete (1) Self MrT
File names sensible, work complete and well-
Presentation & presented. Filed in order of topic, and easy to
NA access. All command terms highlighted or
Organisation
underlined.
Sources cited using the CSE (ISO 690 numerical)
Academic
NA method, with Works Cited section complete and
Honesty correct.
All answers for the following command terms Most answers for the following command terms
Objective 1
correct: correct:
understanding Define Draw Label List Measure State
Most answers for the following command terms
Objective 2 All answers for the following command terms correct:
correct:
understanding Annotate Apply Calculate Describe Distinguish Estimate Identify Outline
Most answers for the following command terms
All answers for the following command terms correct:
Objective3 correct:
understanding Analyse Comment Compare Construct Deduce Derive Design Determine Discuss
Evaluate Explain Predict Show Solve Sketch Suggest
Logic, notation, Answers are presented in a logical and concise
manner. SI units used most times, with correct
mathematical NA unit symbols and definitions of terms. All
working mathematical working shown.
Evidence is apparent of research and reading
beyond the textbook and presentations to find
Further research NA correct answers to challenging questions. If any
questions are unanswered, this criterion scores
zero.
Total (max 10):
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