(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, the p-value becomes Ho becomes to be rejected, and the power of the test 37

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question

Don't do the cross(x) part of the question do the rest 

g, a and b 
please do the calculation by hand so I can understand them tha

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
Expert Solution
steps

Step by step

Solved in 2 steps with 2 images

Blurred answer
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman