Sophia __ Intro to Statistics_ Milestone 5.
Score
23/24
You passed this Milestone
23 questions were answered correctly. 1 question was
answered incorrectly. 1
Select the statement that correctly describes a Type I
error.
A Type I error occurs when the null hypothesis is rejected when it is actually
true.
A Type I error occurs when the null hypothesis is rejected when it is actually false.
UNIT 5 — MILESTONE 5
A Type I error occurs when the null hypothesis is accepted when it is actually false.
A Type I error occurs when the null hypothesis is accepted when it is actually true.
https://app.sophia.org/spcc/introduction-to-statistics-2/ 1/22
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, Sophia __ Intro to Statistics_ Milestone 5.
RATIONALE
Recall a Type I error is when we incorrectly reject a true null hypothesis. So we would reject H₀ using sample
evidence, when in fact it was not true.
CONCEPT
Type I/II
Errors 2
Adam tabulated the values for the average speeds on each day of his road trip as 60.5, 63.2, 54.7, 51.6, 72.3,
70.7, 67.2, and 65.4 mph. The sample standard deviation is 7.309.
Select the 98% confidence interval for Adam’s set of data.
https://app.sophia.org/spcc/introduction-to-statistics-2/ 2/22
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, Sophia __ Intro to Statistics_ Milestone 5.
46.94 to 79.46
55.45 to 79.46
55.45 to
46.94 to 71.33
RATIONALE
In order to get the 98% CI , we first need to find the critical
t-score. Using a t-table, we need to find (n-1) degrees of freedom, or (8-1) = 7 df and the corresponding CI.
Using the 98% CI in the bottom row and 7 df on the far left column, we get a t-critical score of 2.998.
We also need to calculate the mean:
So we use the formula to find the confidence interval:
The lower bound is:
63.2-7.75 = 55.45
The upper bound is:
https://app.sophia.org/spcc/introduction-to-statistics-2/ 3/22
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, Sophia __ Intro to Statistics_ Milestone 5.
63.2+7.75 = 70.95
CONCEPT
Confidence Intervals Using the T-
Distribution 3
For a left-tailed test, the critical value of z so that a hypothesis test would reject the null
hypothesis at 1% significance level would be . Answer choices are rounded to the
hundredths place.
-1.03
https://app.sophia.org/spcc/introduction-to-statistics-2/ 4/22
milestone_take_feedbacks/9755471
Score
23/24
You passed this Milestone
23 questions were answered correctly. 1 question was
answered incorrectly. 1
Select the statement that correctly describes a Type I
error.
A Type I error occurs when the null hypothesis is rejected when it is actually
true.
A Type I error occurs when the null hypothesis is rejected when it is actually false.
UNIT 5 — MILESTONE 5
A Type I error occurs when the null hypothesis is accepted when it is actually false.
A Type I error occurs when the null hypothesis is accepted when it is actually true.
https://app.sophia.org/spcc/introduction-to-statistics-2/ 1/22
milestone_take_feedbacks/9755471
, Sophia __ Intro to Statistics_ Milestone 5.
RATIONALE
Recall a Type I error is when we incorrectly reject a true null hypothesis. So we would reject H₀ using sample
evidence, when in fact it was not true.
CONCEPT
Type I/II
Errors 2
Adam tabulated the values for the average speeds on each day of his road trip as 60.5, 63.2, 54.7, 51.6, 72.3,
70.7, 67.2, and 65.4 mph. The sample standard deviation is 7.309.
Select the 98% confidence interval for Adam’s set of data.
https://app.sophia.org/spcc/introduction-to-statistics-2/ 2/22
milestone_take_feedbacks/9755471
, Sophia __ Intro to Statistics_ Milestone 5.
46.94 to 79.46
55.45 to 79.46
55.45 to
46.94 to 71.33
RATIONALE
In order to get the 98% CI , we first need to find the critical
t-score. Using a t-table, we need to find (n-1) degrees of freedom, or (8-1) = 7 df and the corresponding CI.
Using the 98% CI in the bottom row and 7 df on the far left column, we get a t-critical score of 2.998.
We also need to calculate the mean:
So we use the formula to find the confidence interval:
The lower bound is:
63.2-7.75 = 55.45
The upper bound is:
https://app.sophia.org/spcc/introduction-to-statistics-2/ 3/22
milestone_take_feedbacks/9755471
, Sophia __ Intro to Statistics_ Milestone 5.
63.2+7.75 = 70.95
CONCEPT
Confidence Intervals Using the T-
Distribution 3
For a left-tailed test, the critical value of z so that a hypothesis test would reject the null
hypothesis at 1% significance level would be . Answer choices are rounded to the
hundredths place.
-1.03
https://app.sophia.org/spcc/introduction-to-statistics-2/ 4/22
milestone_take_feedbacks/9755471
