take an exam, then let them use the practice questions to hone their statistical skills, and
finally asked the same students to retake the exam. We analyzed the results using a two-
sample t-test and found a significant result (p=0.012). The p-value indicates that our
practice questions are guaranteed to improve your score 99.8% of the time!
10)
For STUDY C, which of the following is the most important methodological error
found in the passage?
(Multiple answers possible: 1 mark for each correct response.
You will lose 0.5 marks for each incorrect answer, but only applied to this question.)
A.
The study design has pseudoreplicated sampling units
B.
The study design has biased sampling unit allocation
C.
The study design uses non-random sampling units
D.
The study design is missing a control level needed to compare.
E.
There are no methodical errors
ANSWER: ____C_____

11)
For STUDY C, which of the following is an error found in the passage?
[1 mark]
I.
Testing the study methods should not be done using linear regression.
II.
Linear regression is not evaluated using a t-test.
III.
There is a mismatch between the test scores and the statistical conclusion.

12)
For STUDY C, which of the following is an error found in the passage?
[1 mark]
I.
Evaluating the relationship between sleep and stress should not be done with a
Chi-square test.
II.
Evaluating the effectiveness of the practice questions on exam success should
not be done using a two-sample t-test.
III.
The researchers have drawn an incorrect scientific
conclusion about the p-
value for the effectiveness of the practice questions on exam success.

STUDY D
Use the following study to answer questions 13, 14 & 15.
Airbnb is an accommodation-sharing platform that relies heavily on guest ratings.
Interestingly, the distribution of ratings (shown below) is not equal across the possible
scores and is also not Normally distributed (5.0 is excellent, 1.0 is poor).
The proportion
of accommodations in each category is:
Rank 5.0 is 46.3%
Rank 4.5 is 41.1%
Rank 4.0 is 10.3%
Rank 3.5 is 1.7%
Rank 3.0 is 0.3%
Rank 2.5 is 0.2%
Rank 2.0 is 0.1%
Rank 1.5 is 0%
Rank 1.0 is 0%
13)
If you took repeated samples of potential accommodations for STUDY D, which of
the following statements about the distribution of the mean ratings would be
INCORRECT?
[1 mark]

5

6