I don’t know The answer but I tried
Ming needs to play for 15 hours to get 500 points. They gave him 200 for signing up, so 500-200=300 more points needed. 300 divided by 20= 15 more hours.
Α = 1- (95/100) = 1-0.95 = 0.05
p = 1- α/2 = 1- 0.05/2 = 1-0.025 = 0.975
Degrees of freedom, df = Sample size -1 = 11-1 = 10
From t-tables, with cumulative probability pf 0.975 and df of 10,
Critical value = 2.228
You are not giving enough information but in one of the calsses the average of student's height might be greater than the other class beacause one of the two classes needs to have 1 extra person than the other calss
