Compute the critical value za/2 that corresponds to a 85% level of confidence.

To compute the critical value za/2 that corresponds to a 85% level of confidence, we need to determine the value of za/2 such that the area under the standard normal curve between -za/2 and za/2 is equal to 0.85.

Since the standard normal distribution is symmetric, we can find the critical value by finding the z-score corresponding to the area between the mean and za/2.

The area to the right of za/2 is (1 - 0.85) = 0.15, which corresponds to the area to the left of za/2.

We can use a standard normal distribution table or statistical software to find the z-score that corresponds to an area of 0.15. Looking up this value, we find that it is approximately 1.036.

Therefore, the critical value za/2 that corresponds to a 85% level of confidence is approximately 1.036.

To compute the critical value, za/2, that corresponds to a specific level of confidence, we can use a Z-table or a statistical calculator.

The critical value, za/2, corresponds to the Z-score that separates the area of interest (1 - α) from the remaining tail area α/2.

In this case, we are looking for a 85% level of confidence, which means we have α = 1 - 0.85 = 0.15. Since we want to find the critical value that corresponds to α/2, we divide α by 2, giving α/2 = 0.15/2 = 0.075.

Using a Z-table or a statistical calculator, we can find the Z-score that corresponds to a cumulative probability of 1 - 0.075 = 0.925.

For example, using a Z-table or a calculator, we find that the Z-score corresponding to a cumulative probability of 0.925 is approximately 1.44.

Therefore, the critical value, za/2, that corresponds to a 85% level of confidence is approximately 1.44.

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