A group of college students believes the average grades in psychology courses are different than the average grades in biology courses. The group found the average psychology grades of a sample of 11 students was 84.4 and the average biology grades of a sample of 11 students was 78.2. What is the null hypothesis for this study?
A) H0: µ = 84.4 and 78.2
B) H0: µpsychology = 84.4 and H0: µbiology = 78.2
C) H0: µpsychology + µbiology = 162.6
D) H0: µpsychology = µbiology