Find the critical value z subscript c necessary to form a confidence interval at the level of confidence shown below. cequals0.89

Z_c = 1.6

Step-by-step explanation:

Solution:-

- The Z-critical value for any Confidence Interval (CI) corresponds to the significance level α. The significance level is defined as:

                             α = 1 - CI

                             α = 1 - 0.89

                             α = 0.11

- The Z-critical occurs at half of the significance value for "Two Tailed" tests.

                             α/2 = 0.11/2 = 0.055

- Then we use the standard normal distribution table or statistics tool. And compute:

                             Z_c = Z_a/2 = Z_0.055

                             Z_0.055 = invNorm ( 0.055 ) = 1.6

Hence,                  Z_c = 1.6