Students applying to graduate schools in many disciplines are required to take the Graduate Record Examination (GRE). An ambitious undergraduate student creates a study program that she believes will greatly increase students' GRE scores, relative to the general population. She recruits a sample of 100 students believed to be representative of the larger undergraduate student population and puts them through the study program. Afterwards, they complete the GRE and receive a mean score of M = 720. The population of GRE scores is normally distributed with a mean of = 1100 and a standard deviation of = 200.

a) What are the null and alternative hypotheses for this research study?

b) An analysis conducted to determine whether the GRE scores for a sample of students who completed this program were higher than the general population yielded z = 2.24, p= .025. If the researcher uses a = .01 as their criteria for identifying a significant difference or effect, what decision would they make about the null hypothesis and why?