Question 9

For a test of the population proportion, what is the distribution of the test statistic?

Question 9 options:

- Chi-squared

- F

- T

- Z

Question 10

H0: 16.99 vs. HA: > 16.99

What is the test statistic for sample of size 30, mean 12.55, and standard deviation 2.00? Enter the test statistic with 2 decimal places.

Your Answer:

Hint for Question 10:

The standardized sample statistic is called the test statistic. We can use the probability distribution of test statistic to decide if the sample statistic is far enough from H0 to reject it.

What are we testing? In the Week 8 Presentation, slide 8, in the applicable row of Test and in column Test Statistic, is the formula of the test statistic.

Question 11

A sample of size 20 yields a sample mean of 23.5 and a sample standard deviation of 4.3.

Test H0: Mean 25 at = 0.10.

Question 11 options:

- Pvalue 0.068. H0 rejected. Conclude mean

- Pvalue 0.932. H0 not rejected. Conclude mean 25 plausible

- None of the answers match my calculation.

- Pvalue 0.135. H0 not rejected. Conclude mean 25 plausible

Hint for Question 11:

Test H0: Mean 25 is tested. What kind of test is this? The standardized sample statistic is called the test statistic. We use the probability distribution of test statistic to decide if the sample statistic is far enough from H0 to reject it. In the Week 8 Presentation, slide 4, in the applicable row of Test and in column Test Statistic, are the applicable Formulas and Functions.

Slide 22 summarizes the Decision rules. Compare the test statistic to the critical value and compare the p-value to alpha.

Question 12

The results of sampling independent populations:

sample 1 from population 1

• mean 80
• population variance 3
• sample size 25

sample 2 from population 2

• mean 81
• population variance 2
• sample size 50

Test H0: (population1 mean - population2 mean) 0 at = 0.05.

HA: (population1 mean - population2 mean) > 0.

Question 12 options:

- None of the answers match my calculation.

- Pvalue 0.9938. H0 not rejected. Conclude difference of means 0 is plausible

- Pvalue 0.0062. H0 rejected. Conclude difference of means > 0.

- Pvalue 0.0124. H0 rejected. Conclude difference of means > 0.

Hint for Question 12:

The standardized sample statistic (distance from parameter to sample statistic in standard errors) is called the test statistic. We use the probability distribution of test statistic to decide if the sample statistic is far enough from H0 to reject H0.

What kind of test is H0: (population1 mean - population2 mean) 0?

The population variances are known.

To be consistent with H0, compute the difference of the means = population1 sample mean - population2 sample mean.

Compare the test statistic to the critical value and compare the p-value to alpha.

Question 13

The results of sampling independent populations:

sample 1 from population 1

• mean 1000
• sample standard deviation 400
• sample size 50

sample 2 from population 2

• mean 1250
• sample standard deviation 500
• sample size 75

Test the H0: population1 mean = population2 mean at = 0.01.

HA: population1 mean population2 mean. Assume the variances are separate.

Question 13 options:

- Test statistic of -65.28 > Critical value of -1.29. H0 rejected. Conclude difference of means = 0

- Test statistic of -3.09

- None of the answers match my calculation.

- Test statistic of 65.28 > Critical value of -2.36. H0 is not rejected. Conclude difference of means = 0.

- None of the answers match my calculation result.

- Test statistic of -3.09

Hint for Question 13:

The standardized sample statistic (distance from parameter to sample statistic in standard errors) is called the test statistic. We use the probability distribution of test statistic to decide if the sample statistic is far enough from H0 to reject H0.

What kind of test is H0: population1 mean = population2?

The population variances are unknown.

Unless specified, assume the variances are unequal.

The DF calculation is complicated. You can use Excel file in DF.

Compare the test statistic to the critical value and compare the p-value to alpha.