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A university president believes that, over the past few years, the average age of students attending his university has changed. To test this hypothesis, an experiment is conducted in which the age of 20 students, who have been randomly sampled from the student body, is measured. The mean age of these 20 students is 25 years. A complete census taken at the university a few years before the experiment showed a mean age of 23 years, with a standard deviation of 7. Assume that the population standard deviation is 7 and the population data are normally distributed. X(a) State the suitable null and alternative hypotheses that address the research question. (b) Compute the z-statistic for our sample data. Show work. X (c) Based on the z-statistic, compute the p-value. Show work and attach R code. (d) Suppose a = 0.05. Based on the p-value, decide whether you can reject the null. X(e) Using the same a level, compute the upper critical value for the z-test. Show work and attach R code. X(f) Compare the upper z-critical with the z-statistic and decided whether you can reject the null. Did you reach the same conclusion as part (d)? (g) Compute the 95% confidence intervals for the mean. Suppose we have the same scenario as the above question except the sample size n changes. (a) Suppose the sample size changes from n 20 to n = 100. What are the new z- statistic and p-value? Are we more likely or less likely to reject the null hypothesis? (b) Based on your answer in the previous part, complete the following sentence. "As the sample size increases, the z-statistic becomes Ho becomes to be rejected, and the power of the test the p-value becomes 39

A university president believes that, over the past few years, the average age of students attending his university has changed. To test this hypothesis, an experiment is conducted in which the age of 20 students, who have been randomly sampled from the student body, is measured. The mean age of these 20 students is 25 years. A complete census taken at the university a few years before the experiment showed a mean age of 23 years, with a standard deviation of 7. Assume that the population standard deviation is 7 and the population data are normally distributed. X(a) State the suitable null and alternative hypotheses that address the research question. (b) Compute the z-statistic for our sample data. Show work. X (c) Based on the z-statistic, compute the p-value. Show work and attach R code. (d) Suppose a = 0.05. Based on the p-value, decide whether you can reject the null. X(e) Using the same a level, compute the upper critical value for the z-test. Show work and attach R code. X(f) Compare the upper z-critical with the z-statistic and decided whether you can reject the null. Did you reach the same conclusion as part (d)? (g) Compute the 95% confidence intervals for the mean. Suppose we have the same scenario as the above question except the sample size n changes. (a) Suppose the sample size changes from n 20 to n = 100. What are the new z- statistic and p-value? Are we more likely or less likely to reject the null hypothesis? (b) Based on your answer in the previous part, complete the following sentence. "As the sample size increases, the z-statistic becomes Ho becomes to be rejected, and the power of the test the p-value becomes 39

MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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A university president believes that, over the past few years, the average age of students attending his university has changed. To test this hypothesis, an experiment is conducted in which the age of 20 students, who have been randomly sampled from the student body, is measured. The mean age of these 20 students is 25 years. A complete census taken at the university a few years before the experiment showed a mean age of 23 years, with a standard deviation of 7. Assume that the population standard deviation is 7 and the population data are normally distributed. X(a) State the suitable null and alternative hypotheses that address the research question. (b) Compute the z-statistic for our sample data. Show work. X (c) Based on the z-statistic, compute the p-value. Show work and attach R code. (d) Suppose a = 0.05. Based on the p-value, decide whether you can reject the null. (e) Using the same a level, compute the upper critical value for the z-test. Show work and attach R. code. (f) Compare the upper z-critical with the z-statistic and decided whether you can reject the null. Did you reach the same conclusion as part (d)? (g) Compute the 95% confidence intervals for the mean. Suppose we have the same scenario as the above question except the sample size n changes. (a) Suppose the sample size changes from n = 20 to n = 100. What are the new z- statistic and p-value? Are we more likely or less likely to reject the null hypothesis? (b) Based on your answer in the previous part, complete the following sentence. "As the sample size increases, the z-statistic becomes Ho becomes -, the p-value becomes to be rejected, and the power of the test 33
Transcribed Image Text:A university president believes that, over the past few years, the average age of students attending his university has changed. To test this hypothesis, an experiment is conducted in which the age of 20 students, who have been randomly sampled from the student body, is measured. The mean age of these 20 students is 25 years. A complete census taken at the university a few years before the experiment showed a mean age of 23 years, with a standard deviation of 7. Assume that the population standard deviation is 7 and the population data are normally distributed. X(a) State the suitable null and alternative hypotheses that address the research question. (b) Compute the z-statistic for our sample data. Show work. X (c) Based on the z-statistic, compute the p-value. Show work and attach R code. (d) Suppose a = 0.05. Based on the p-value, decide whether you can reject the null. (e) Using the same a level, compute the upper critical value for the z-test. Show work and attach R. code. (f) Compare the upper z-critical with the z-statistic and decided whether you can reject the null. Did you reach the same conclusion as part (d)? (g) Compute the 95% confidence intervals for the mean. Suppose we have the same scenario as the above question except the sample size n changes. (a) Suppose the sample size changes from n = 20 to n = 100. What are the new z- statistic and p-value? Are we more likely or less likely to reject the null hypothesis? (b) Based on your answer in the previous part, complete the following sentence. "As the sample size increases, the z-statistic becomes Ho becomes -, the p-value becomes to be rejected, and the power of the test 33
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