Answer to Question #129957 in Statistics and Probability for Azleen Nur Khaziyanti Aziz

Question

In one of the hypothesis study, Robin considers to increase the alpha level. Briefly explain the effect on the Type I and Type II errors together with the probability weather he should reject the null hypothesis.

Answer 1

Type I error is the error of rejecting a null hypothesis when it is actually true. Alpha is the probability of making Type I error. So, if alpha increases, the probability of the Type I error increases.

Type II error is the error of not rejecting a null hypothesis when the alternative hypothesis is true. So, if alpha increases, the probability of the Type II error decreases.

If alpha increases, the probability that the P-value will lie in the critical region increases. So, the probability of rejecting the null hypothesis increases. Type I error is often represented by the Greek letter alpha (α) and a Type II error by the Greek letter beta (β )

In order to graphically depict a Type II, or β, error, it is necessary to imagine next to the distribution for the null hypothesis a second distribution for the true alternative.