In testing at the 5% significance level, a sample of size 20 is used. The rejection region is:
A) -.377. 377
B) .777 or-.377
C) .450 or-.450
D) -.450. 450
E) none of these

Question

In testing  at the 5% significance level, a sample of size 20 is used. The rejection region is:
A) -.377. 377 
B) .777 or-.377 
C) .450 or-.450 
D) -.450. 450 
E) none of these

Quizplus · Accepted Answer

Since the significance level is 5%, we have alpha=0.05. We are testing at the 5% significance level which is equivalent to a critical value of 1-alpha/2 = 0.975. Since the sample size is 20, the degrees of freedom is 20-1=19. Therefore, using a t-distribution table, we find the critical values to be approximately +/- 2.093. Since we are conducting a two-tailed test, the rejection region is t< -2.093 or t> 2.093, which is equivalent to t< -0.450 or t> 0.450. Thus, the correct choice is C, which includes both values in the rejection region.

In Testing at the 5% Significance Level, a Sample