Question

Using the .01 criterion of significance, the probability of making a Type II error is _____? Please explain how the probability using a = .01 is different for Type 1 and Type II errors.

Answer 1

There are two type of error in hypothesis testing.

Type-1 error occur, when we reject the null hypothesis but it is true.

Type-2 error occur, When we fail to reject the null hypothesis but it is false.

Type one error is denoted as alpha, which is level of significance and type two error is denoted as beta which is called the power of the test.

Let's understand with an example

We have the hypothesis

H0: There is no effect of drug

Ha: There is significant effect of drug

Type-1 error, There is no effect of drug but we concluded that there is significant effect of drug.

Type-2 error, There is significant effect of drug but we concluded that there is no effect of drug.

Actually type-1 and type-2 error are the probability.

We know that the sum of probability is one

Alpha + beta = 1

Where alpha = 0.01 (given)

0.01 + beta = 1

beta = 1 - 0.01 = 0.99