In a sample of n=25 adolescents, the mean was calculated to be M=77.5. The normal population has a mean of = 80 and a standard deviation of =12. Does the sample provide evidence conclude that the sample is significantly different from those of the general population? Use a two-tail test with = 0.05.

2a)What is the null and alternative hypothesis?

2b) What is the negative value ofzcrit (the cut off for the critical region)?

2c) What is M?

2d) What is zobt?

2e) What conclusion do you draw?