Since changing this statistics course to a new format I would like to be able to detect an increase of one letter grade (5 point increase) in the overall average of my students. The population mean grade is 78, with a standard deviation of 6 points. Determine the sample size needed to detect an increase of 5 points. Let ? = 0.02 and ? = 0.05 (10 points)
a) Write the null and alternative hypotheses
b) Draw the curves and label ? and ?
c) Calculate the sample size