The NORMDIST function in Excel is an essential statistical tool that calculates the cumulative distribution function for a specified normal distribution. It is useful for analyzing data that follows a normal distribution pattern, whether to determine probabilities or z-scores.

Syntax

NORMDIST(x, mean, standard_dev, cumulative)

x: The value for which you want the distribution.
mean: The arithmetic mean of the distribution.
standard_dev: The standard deviation of the distribution.
cumulative: A logical value that determines the form of the function. Use TRUE for the cumulative distribution and FALSE for the probability density function.

Example #1

=NORMDIST(65, 70, 10, TRUE)

This example calculates the cumulative distribution for a value of 65, with a mean of 70 and a standard deviation of 10, yielding a result of approximately 0.1587.

Example #2

=NORMDIST(80, 75, 5, FALSE)

In this case, the function computes the probability density at a value of 80, with a mean of 75 and a standard deviation of 5, resulting in around 0.0480.

Example #3

=NORMDIST(40, 50, 15, TRUE)

This function call returns the cumulative probability for 40, against a distribution mean of 50 and a standard deviation of 15, resulting in approximately 0.1587.

Error handling

• VALUE! Occurs when one or more arguments are non-numeric.
• NUM! This error surfaces if ‘standard_dev’ is less than or equal to zero.
• NAME? Appears when Excel does not recognize the function name, possibly due to misspelling.

Conclusion

The NORMDIST function is a powerful Excel tool for statistical analysis, particularly for datasets that conform to a normal distribution. By utilizing this function, users can easily compute probabilities and understand their data’s distribution characteristics, aiding in informed decision-making based on statistical evidence.