STT 231 Exam 3 2026 Exam
Questions and Answers | 100%
Pass
A study was conducted to identify the factors affecting quality of sleep for
university students. A survey of 290 students of different majors aged 17-
29 years old revealed that 67.2% of these students suffered from poor
sleep.Further analyses were conducted based off the original study of
290 university students in the question above. A second study assessed
if the distribution of sleep quality was the same for the various age
groups of Young (19 years old or younger), Middle (over19 but less than
24 years old), and Old (24 years and older) university students. The
following data shows the sleep quality results for each group.a. Select
,the name of the test that should be used to assess if the distribution of
the responses is the same for the three age-group populations
𝜒 ^2 test of independence or 𝜒^2 goodness of fit test - ANSWER
✔✔𝜒^2 test of independence
chi squared test of independence - ANSWER ✔✔A statistical test in
which both variables are categorical. This test generally tells us if the
distribution of participants across categories is different from what would
happen if there were no difference between the groups
Squared test statistic has two consequences - ANSWER ✔✔1. all x^2
statistics are positive
2. cells that are already unusual are further emphasized (side effect)
Chi-square distributions are skewed to the ______ and take on only
_______ values. - ANSWER ✔✔Right, positive
What is standard deviation in chi-squared? - ANSWER ✔✔sqrt(2df)
chi squared goodness of fit - ANSWER ✔✔A hypothesis test that
assesses whether the distribution of a single categorical variable follows
a proposed distribution.
, Using the 𝜒 2 statistic, it compares the observed counts with the counts
we would expect to see if the observed data perfectly obeyed the
proposed distribution.
USES A SINGLE CATEGORICAL VARIABLE.
degrees of freedom - ANSWER ✔✔k-1 k being categories
Computing expected counts for a two-way table (Cross-product rule) -
ANSWER ✔✔expected value = (column total)(row total) / overall total
If the distribution of the sleep quality is the same for the three age
populations of university students, what is the expected value of the test
statistic? - ANSWER ✔✔2
If the distribution of sleep quality is the same for the three age
populations of university students, (i.e., if sleep quality is independent of
age group) how would you determine the expected count of young
students reporting "good"quality sleep? [Set up the calculation you would
perform using values from the table of results; you do not need to
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
Questions and Answers | 100%
Pass
A study was conducted to identify the factors affecting quality of sleep for
university students. A survey of 290 students of different majors aged 17-
29 years old revealed that 67.2% of these students suffered from poor
sleep.Further analyses were conducted based off the original study of
290 university students in the question above. A second study assessed
if the distribution of sleep quality was the same for the various age
groups of Young (19 years old or younger), Middle (over19 but less than
24 years old), and Old (24 years and older) university students. The
following data shows the sleep quality results for each group.a. Select
,the name of the test that should be used to assess if the distribution of
the responses is the same for the three age-group populations
𝜒 ^2 test of independence or 𝜒^2 goodness of fit test - ANSWER
✔✔𝜒^2 test of independence
chi squared test of independence - ANSWER ✔✔A statistical test in
which both variables are categorical. This test generally tells us if the
distribution of participants across categories is different from what would
happen if there were no difference between the groups
Squared test statistic has two consequences - ANSWER ✔✔1. all x^2
statistics are positive
2. cells that are already unusual are further emphasized (side effect)
Chi-square distributions are skewed to the ______ and take on only
_______ values. - ANSWER ✔✔Right, positive
What is standard deviation in chi-squared? - ANSWER ✔✔sqrt(2df)
chi squared goodness of fit - ANSWER ✔✔A hypothesis test that
assesses whether the distribution of a single categorical variable follows
a proposed distribution.
, Using the 𝜒 2 statistic, it compares the observed counts with the counts
we would expect to see if the observed data perfectly obeyed the
proposed distribution.
USES A SINGLE CATEGORICAL VARIABLE.
degrees of freedom - ANSWER ✔✔k-1 k being categories
Computing expected counts for a two-way table (Cross-product rule) -
ANSWER ✔✔expected value = (column total)(row total) / overall total
If the distribution of the sleep quality is the same for the three age
populations of university students, what is the expected value of the test
statistic? - ANSWER ✔✔2
If the distribution of sleep quality is the same for the three age
populations of university students, (i.e., if sleep quality is independent of
age group) how would you determine the expected count of young
students reporting "good"quality sleep? [Set up the calculation you would
perform using values from the table of results; you do not need to
3
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2026. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
