A certain test of hypothesis based on the normal distributio

A certain test of hypothesis based on the normal distribution was evaluated at the 2.5% level of significance. Assuming a two-tailed test the critical (or rejection) region in the upper tail contains the following percentage of total area under the standard normal curve: a. 1.25% b. 2.5% c. 5.0% d. 95.0% e. none of the above

Solution

area in 2 tails = 2.5% = 0.025, in upper tail = 0.025/2 = 0.0125 = 1.25%