find the levels of the confidence intervals that have the given critical values.

Question

question 25: 2.326

Question 27:2.81

Answer 1

z-score 2.326 corresponds to probability 0.99. That is the z-score for the upper limit of the CI. The z-score for the lower limit of the CI will be -2.326, which corresponds to probability 0.01. The difference between those two probabilities is 0.99 - 0.01 = 0.98, which converts to 98%

z-score 2.81 corresponds to probability 0.998. That is the z-score for the upper limit of the CI. The z-score for the lower limit of the CI will be -2.81, which corresponds to probability 0.002. The difference between those two probabilities is 0.998- 0.002 = 0.996, which converts to 99.6%