AP Statistics Test Statistic

To test a claim about a mean, when the population standard deviation is unknown we use:

• z procedures

• Pythagorean Theorem

• t procedures

• np > 10 and n(1-p) > 10

You have an SRS of 23 observations from large population. The distribution of sample values is roughly symmetric with no outliers. What critical value would you use to obtain a 98% confidence interval for the mean of the population?

• 2.177

• 2.183

• 2.326

• 2.500

• 2.508

What test should be used?

• 2 proportion z test

• 1 proportion z test

• 2 sample t test for means

• 1 sample t test for mean

What test should be performed?

• Paired t test

• 1 sample t test for mean difference

• 2 proportion z test

• 2 sample t test for difference in means

What test should be used?

• 2 Sample t test for difference in means

• 2 proportion z test

• Paired t test

• 1 sample z test

Mrs. Trahan claims that her students' average score on the AP exam is 3.9. A random sample of 50 of her students' scores produce a mean score of 3.1 with a standard deviation of 1.5. Does this sample show evidence that Mrs. Trahan is overstating her average score?

• With a test statistic of -3.8 which is unlikely, it seems that Mrs. Trahan may be overstating her average AP score.

• With a test statistic of -4.7 which is unlikely, it seems that Mrs. Trahan may be overstating her average AP score.

• With a test statistic of -0.53 which is not unusual and this sample does not show evidence that Mrs. Trahan is overstating her average AP score.

A sample of 25 Ohio students who have taken the ACT have a sample mean score of 21.  What is the critical value used to build a 95% confidence interval for the true mean ACT score for all Ohio students?

• 2.064

• 2.086

• 1.96

• 2.060

A random sample of 25 Ohio students had a mean ACT score of 21 with a standard deviation of 1.2.  Which of the following is the 95% confidence interval for the true average ACT score for Ohio students?

• (20.53, 21.47)

• (18.648, 23.352)

• (20.505, 21.495)