Question

Find the critical z value for a confidence level of 85%. (round answer to 2 decimal places)

Answer 1

The critical z-value for a confidence level of 85% is ±1.439.

Explanation:

The critical value of a distribution is the value beyond which the rejection region lies.

For a confidence interval the rejection region lies beyond two values, the positive and the negative critical value.

The confidence level is, 85%.

Compute the critical value of z for 85% confidence level as follows:

`\pm z_(\alpha/2)=\pm z_(0.15/2)=\pm z_(0.075)=\pm1.439`

*Use a z-table for the value.

Thus, the critical z-value for a confidence level of 85% is ±1.439.