How to Use the NORM.INV Function in Excel
Today, we’ll explore the NORM.INV function in Excel and Google Sheets, a powerful tool used to find the inverse of the normal cumulative distribution for specified mean and standard deviation values. Essentially, it calculates the value corresponding to a given probability in a normal distribution.
Basic Syntax
The structure for the NORM.INV function is:
NORM.INV(probability, mean, standard_dev)- Probability: The probability corresponding to the desired point in the distribution.
- Mean: The mean (average) of the distribution.
- Standard_dev: The standard deviation, which measures the dispersion of the data points from the mean.
Examples of Usage
To better understand how the NORM.INV function works, let’s review some practical examples:
Example 1: Finding the Inverse of a Standard Normal Distribution
Consider we need to determine the data value associated with a cumulative probability of 0.75 in a standard normal distribution, which has a mean (μ) of 0 and a standard deviation (σ) of 1.
| Value | Formula | Result |
|---|---|---|
| Inverse | =NORM.INV(0.75, 0, 1) | 0.67448975 |
The value corresponding to a cumulative probability of 0.75 in a standard normal distribution is approximately 0.6745.
Example 2: Finding the Inverse for a Non-Standard Normal Distribution
For a non-standard normal distribution with a mean of 10 and a standard deviation of 2, let’s find the value associated with a probability of 0.95.
| Value | Formula | Result |
|---|---|---|
| Inverse | =NORM.INV(0.95, 10, 2) | 13.28970725 |
In this non-standard normal distribution, the value that corresponds to a cumulative probability of 0.95 is approximately 13.2897.
These examples illustrate how the NORM.INV function can be effectively used to compute inverses of both standard and non-standard normal distributions in Excel and Google Sheets. Always ensure that the values for probability, mean, and standard deviation are accurately entered to achieve correct results.
More information: https://support.microsoft.com/en-us/office/norm-inv-function-54b30935-fee7-493c-bedb-2278a9db7e13