NORMSINV

NORMSINV is a statistical function available in many spreadsheet programs and statistical software. It stands for "Normal Standard Inverse" and calculates the inverse of the standard normal cumulative distribution. In simpler terms, it takes a probability value (a number between 0 and 1) and returns the z-score such that the area under the standard normal curve to the left of that z-score is equal to the given probability.

The standard normal distribution is a special case of the normal distribution where the mean is 0 and the standard deviation is 1. The NORMSINV function is useful for various statistical tasks, such as finding critical values for hypothesis testing or determining confidence intervals when you know the desired probability. For example, if you want to find the z-score that cuts off the top 5% of the distribution, you would input 0.95 into the NORMSINV function, as 0.95 represents the area to the left of that z-score. The function returns the corresponding z-score, which is approximately 1.645.

The input to NORMSINV must be a numeric value between 0 and 1, exclusive. If the input is less than or equal to 0 or greater than or equal to 1, the function will return an error. NORMSINV is the inverse of the NORMSDIST function, which calculates the cumulative probability for a given z-score.

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