How to calculate confidence interval

To calculate the z-score for a confidence interval, find the complement of the confidence level (1 - C), divide by 2, then use a z-table or calculator to find the z-score corresponding to the cumulative probability (1 - α/2).

z-score represents the number of standard deviations a data point is from the mean of a standard normal distribution.

Let's discuss the steps to calculate z-score of confidence interval with example for better understanding.

Steps to Calculate z-score of Confidence Interval

Here are the steps to calculate the z-score for a given confidence interval:

Step 1: Determine the Confidence Level: Common confidence levels are 90%, 95%, and 99%.

Let's denote the confidence level as C.

Step 2: Find the Complement of the Confidence Level: Calculate α as α = 1 − C.

Step 3: Divide the Complement by 2: This gives α/2, representing the area in each tail of the normal distribution.

Step 4: Find the z-score: Use a z-table or a statistical calculator to find the z-score that corresponds to the cumulative

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