Question

a) If X ~ χ²(80), determine P(57.153 < X < ∞).

.025

.050

.900

.950

.975

b) Suppose that marks on a final exam follow a normal distribution with a mean of 66% and a standard deviation of 7%. On the next final exam, and assuming the class size is 200 students, how many students would you expect will score over 80% on the exam? Choose the closest answer.

5

11

17

23

31

Answer 1

Here

a)P(57.153<x<inf)=0.025

Hence first option is correct.

b)

Number of students will score over 80%=5

Hence first option is correct.

For detailed I have attached the solution.