Module Hypothesis Testing
Hypothesis Testing Checkpoint
Step 1 of 1
Question 1 of 7 Points: 10 out of 10
A study was conducted in order to estimate µ, the mean number of weekly hours that U.S.
adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean
weekly computer usage time of 8.5 hours and that from prior studies, the population standard
deviation is assumed to be σ = 3.6 hours.
A similar study conducted a year earlier estimated that µ, the mean number of weekly hours that
U.S. adults use computers at home, was 8 hours. We would like to test (at the usual significance
level of 5%) whether the current study provides significant evidence that this mean has changed
since the previous year.
Using a 95% confidence interval of (7.7, 9.3), our conclusion is that:
the current study does provide significant evidence that the mean number of weekly hours has
changed over the past year, since 8 falls outside the confidence interval.
the current study does not provide significant evidence that the mean number of weekly hours
has changed over the past year, since 8 falls outside the confidence interval.
the current study does provide significant evidence that the mean number of weekly hours has
changed over the past year, since 8 falls inside the confidence interval.
the current study does not provide significant evidence that the mean number of weekly hours
has changed over the past year, since 8 falls inside the confidence interval.
None of the above. The only way to reach a conclusion is by finding the p-value of the test.
Good job! We are interested in testing: H0: µ = 8 vs. Ha: µ ≠ 8. Since the 95% confidence interval
(7.7, 9.3), contains 8 (in other words, 8 is a plausible value for µ), we do not have enough
evidence to reject H0 and conclude that the mean has changed.
Question 2 of 7 Points: 10 out of 10
Which of the following facts about the p-value of a test is correct?
The p-value is calculated under the assumption that the null hypothesis is true.
The smaller the p-value, the more evidence the data provide against H0.
The p-value can have values between -1 and 1.
All of the above are correct.
Just (A) and (B) are correct.
Hypothesis Testing Checkpoint
Step 1 of 1
Question 1 of 7 Points: 10 out of 10
A study was conducted in order to estimate µ, the mean number of weekly hours that U.S.
adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean
weekly computer usage time of 8.5 hours and that from prior studies, the population standard
deviation is assumed to be σ = 3.6 hours.
A similar study conducted a year earlier estimated that µ, the mean number of weekly hours that
U.S. adults use computers at home, was 8 hours. We would like to test (at the usual significance
level of 5%) whether the current study provides significant evidence that this mean has changed
since the previous year.
Using a 95% confidence interval of (7.7, 9.3), our conclusion is that:
the current study does provide significant evidence that the mean number of weekly hours has
changed over the past year, since 8 falls outside the confidence interval.
the current study does not provide significant evidence that the mean number of weekly hours
has changed over the past year, since 8 falls outside the confidence interval.
the current study does provide significant evidence that the mean number of weekly hours has
changed over the past year, since 8 falls inside the confidence interval.
the current study does not provide significant evidence that the mean number of weekly hours
has changed over the past year, since 8 falls inside the confidence interval.
None of the above. The only way to reach a conclusion is by finding the p-value of the test.
Good job! We are interested in testing: H0: µ = 8 vs. Ha: µ ≠ 8. Since the 95% confidence interval
(7.7, 9.3), contains 8 (in other words, 8 is a plausible value for µ), we do not have enough
evidence to reject H0 and conclude that the mean has changed.
Question 2 of 7 Points: 10 out of 10
Which of the following facts about the p-value of a test is correct?
The p-value is calculated under the assumption that the null hypothesis is true.
The smaller the p-value, the more evidence the data provide against H0.
The p-value can have values between -1 and 1.
All of the above are correct.
Just (A) and (B) are correct.
