Math 221B- L12 Group Quiz

Use the data file Chapter12DataB1.xlsx (Links to an external site.) to answer the next eight questions. Perform a paired samples t-test in Excel. Be sure that the test does Group 1 minus Group 2. This data comes from NosocomialInfections.xlsx. The null hypothesis is H0:μd=0, the alternative hypothesis is Ha:μd≠0, and the level of significance is α=0.01 What is the P-value? (Round to three decimal places)

0.001

Use the following information for the next 2 questions. Suppose we have a set of paired data , and let d=xafter−x before. The null hypothesis is H0:μd=0, the alternative hypothesis is Ha:μd≠0, and the population standard deviation σ is not known. Jordan collects a sample of size n=9 and computes d¯=2.2 and sd=3.3. The probability of obtaining a test statistic greater than Jordan's test statistic is 0.0403. Use this probability to determine the P-value for Jordan's hypothesis test. (Round to three decimal places.)

0.08 or 0.081 (with margin: 0.003)

Use the data file Chapter12DataA1.xlsx (Links to an external site.) to answer the next 6 questions. Perform a paired samples t-test in Excel. Be sure that the test does Group 1 minus Group 2. Use a null hypothesis of H0:μd=0 and alternative hypothesis Ha:μd≠0 and level of significance α=0.10. What is the test statistic? (Round to three decimal places)

0.407 (with margin: 0.003)

Use the following information for the next 2 questions. Suppose we have a set of paired data, and let d=xafter−xbefore. The null hypothesis is H0:μd=0, the alternative hypothesis is Ha:μd≠0, and the population standard deviation σ is not known. Jordan collects a sample of size n=9 and computes d¯=2.2 and sd=3.3. What is the P-value? (Round to three decimal places)

0.689 (with margin: 0.003)

Determine the 95% confidence interval for the mean difference between the two groups (using Group 1 minus Group 2). Input your answers below. What is the point estimate for this 95% confidence interval?

11.955 (with margin: 0.003)

Input the upper bound. (Round to three decimal places.)

18.607 (with margin: 0.003)

Use the following information for the next 2 questions. Suppose we have a set of paired data, and let d=xafter−xbefore. The null hypothesis is H0:μd=0, the alternative hypothesis is Ha:μd≠0, and the population standard deviation σ is not known. Jordan collects a sample of size n=9 and computes d¯=2.2 and sd=3.3. What is the value of the test statistic?

2 (with margin: 0.003)

Input the lower bound. (Round to three decimal places.)

5.303 (with margin: 0.003)

What is the margin of error for this 95% confidence interval?

6.652 (with margin: 0.003)

You decide to try another alternative hypothesis. This time you use Ha:μd>0 and you keep the same level of significance. Did the P-value increase or decrease? Increase Decrease

Decrease

What is the correct decision based on this evidence? Fail to reject the null hypothesis. Reject the null hypothesis.

Fail to reject the null hypothesis.

As we have seen, the P-value depends on the alternative hypothesis. In general, which alternative hypothesis will give the smallest P-value? μd≠0 μd<0 Not enough information, depends on the problem. μd>0

Not enough information, depends on the problem.

Use the data file Chapter12DataB1.xlsx (Links to an external site.) to answer the next eight questions. Perform a paired samples t-test in Excel. Be sure that the test does Group 1 minus Group 2. This data comes from NosocomialInfections.xlsx. The null hypothesis is H0:μd=0, the alternative hypothesis is Ha:μd≠0, and the level of significance is α=0.01 What decision do you make? Reject the null hypothesis. Fail to reject the null hypothesis.

Reject the null hypothesis.

What decision do you make? Reject the null hypothesis. Fail to reject the null hypothesis.

Reject the null hypothesis.

Suppose your alternative hypothesis is instead Ha:μd>0. What is the correct decision based on this evidence? We have insufficient evidence that the mean of the differences is equal to zero. We have insufficient evidence that the mean of the differences is greater than zero. We have sufficient evidence that the mean of the differences is greater than zero. We have sufficient evidence that the mean of the differences is equal to zero.

We have insufficient evidence that the mean of the differences is greater than zero.

Based on your response from the previous question, what conclusion do you make? We have sufficient evidence that there is no mean difference between the two groups. We have insufficient evidence that there is no mean difference between the two groups. We have sufficient evidence that there is a mean difference between the two group. We have insufficient evidence that there is a mean difference between the two groups

We have sufficient evidence that there is a mean difference between the two group.

Use the data file Chapter12DataB1.xlsx (Links to an external site.) to answer the next eight questions. Perform a paired samples t-test in Excel. Be sure that the test does Group 1 minus Group 2. This data comes from NosocomialInfections.xlsx. The null hypothesis is H0:μd=0, the alternative hypothesis is Ha:μd≠0, and the level of significance is α=0.01 Which is greater, n or df?

n