In the population, the average score upon a test of self-esteem is 50 ( st.dev.= 5). You select one sample of 25 students who score a mean of 53.
a. Sally claims these students don't have very high self-esteem, because they are only 3 points above the population mean. Why can't she make this claim merely by looking at the raw scores ?
b. What should she do to determine if this sample is different from the general population?
c. What is the z-score for this sample?
d. What conclusion do you draw about your sample?