# Hypothesis testing : T test

See attached files.

9. The state department of education is interested the length of time it takes students to graduate. As part of the study the department manager wants to determine whether the proportion of all female students graduating in 5 years or less ( out of all females who graduate) is significantly different from the proportion of all male students graduating in 5 years or less (out of all males that graduate). She sampled recent graduates in central Ohio and obtained the following sample data.

(table in attachment)

A. Show all 5 steps of Hypothesis testing and interpret your decision. Points will be deducted for missing steps.

B. Construct a 90% confidence interval for the proportion of women graduating in 5 yearsor less.

C. Interpret and comment on the interval

D. Suppose you wanted to reduce this 90% confidence interval to within 2%of the actual percent. What size of a sample would you need?

10. Test the hypothesis that the average production for three different machines is the same (ie no difference). You may assume that the all populations are independent and nearly normal. Test at the 1% significance level.

(table in attachment)

A. What is the name of the test procedure used for this problem?

B. State the null and alternative hypotheses.

C. Report the test statistic and p-value.

D. What is the decision?

E. What is your conclusion? Explain what this means to someone who is not familiar with statistics. Remember to use full sentences and correct grammar

https://brainmass.com/statistics/hypothesis-testing/hypothesis-testing-t-test-416343

#### Solution Summary

Step by step method for computing test statistic for t test is given in the answer.