Question

A friend of mine believes that the average GPA at KSU is equal to 3.0. In order to test whether he/she is right, I collect some information from the data. Specifically, I use 100 KSU students to form a sample and find that their sample average GPA is equal to 3.3. In addition, suppose that I also know the population standard deviation of GPA at KSU is 1.5. I decide to use 0.05 as the level of significance for my hypothesis testing. Could you help me with Q1-Q10 below?

Q1: What should be my null hypothesis? What should be my alternative hypothesis?

Q2: Is this a lower-tailed, upper-tailed or two-tailed case?

Q3: Show me how to calculate my test statistic.

Q4: If I use the critical value approach, explain how to derive my critical value(s).

Q5: If I use the p-value approach, explain how to derive my p-value.

Q6: If I use the confidence interval approach, show me how to derive the confidence interval.

Q7: How to make my decision, if I use the critical value approach?

Q8: How to make my decision, if I use the p-value approach?

Q9: How to make my decision, if I use the confidence interval approach?

Q10: Are the decisions in Q7, Q8, and Q9 the same?

Answer 1