Question 2:

If the mean difference is zero or close to zero, would you reject or fail to reject the null hypothesis? Explain the reasons for your answer.

Question 3:

When will the true population mean fall outside of a 95% confidence interval?

Question 4:

If we have a 95% confidence interval ranging from +1.5 to + 2.7, can we be wrong in stating, we "reject the null hypothesis"? Explain the reasons for your answer.