Susan goes to her doctor because she thinks she is ill.

(a) What is H0, Ha?

(b) Type I error? Type II error?

(c) Which of the errors are more serious and why?

a) Alternative and null hypotheses:

H0 : Susan is ill

Ha : Susan is not ill

b) Type I error:

In type I error, the null hypothesis, H0 is rejected, even though it is correct.

The type I error here: We conclude Susan is not ill, even though she is ill.

Type II error:

In type II error, we fail to reject null hypothesis, H0, even though it is false.

Type II error here: We conclude Susan is ill, even though she is not ill.

c) The type I error is more serious.

In the type I error here, we conclude Susan is not sick even though she is sick, which is a very dangerous thing to do health wise.