Assume that the data has a normal distribution and the number of observations is greater than fifty. Find the critical z value used to test a null hypothesis.

1) = 0.05 for a left-tailed test.

A) -1.96

B) -1.645

C) 1.645

D) 1.96 8)

2) = 0.05 for a two-tailed test.

A) 1.96

B) 1.645

C) 1.764

D) 2.575