A lecture course has 900 students broken into sections of 30 students each. On the final the average of the whole class is 62 with an SD of 20. However one section has an average of only 52. The TA for the section argues his section's low average is just due to chance variation. The null hypothesis is that this TA is no different than the average TA and that the difference between his section's average and the whole class's average is small and just due to chance.