A February 2007 story on www.redandblack.com stated, “Students who use laptops in class have lower GPAs, according to a study by Cornell University.”
a. Suppose this conclusion was based on a significance test comparing means. Defining notation in context, identify the groups and the population means and state the null hypothesis for the test.
b. Suppose the study conclusion was based on a P-value of 0.01 obtained for the significance test mentioned in part a. Explain what you could learn from a confidence interval comparing the means that you are not able to learn from this P-value.