How to Make the Weibull Distribution in Excel

The Weibull distribution is a continuous probability distribution used in advanced probability and statistics. Microsoft Excel has a built-in function to evaluate the Weibull distribution, which is widely used in reliability theory. The formula is "WEIBULL(x,alpha,beta,cumulative)," where "x" is the value where you want to evaluate the distribution, "alpha" and "beta" are your distribution parameters, and "cumulative" is specified as true or false to indicate the form for the function.

Things You'll Need

• Microsoft Excel 2010 or 2007 worksheet with input data for the Weibull distribution

Instructions

1. Click an empty cell in an Excel worksheet.

2. Type "WEIBULL(x,alpha,beta,cumulative)" into the cell, where "x," "alpha" and "beta" are the cell locations of your parameters. For example, the formula "WEIBULL(B2,B3,B4,TRUE)" tells Excel that the location for the "x" value is cell B2, for "alpha" is cell B3 and for "beta" is cell B4. "TRUE" tells Excel that you want to evaluate a cumulative distribution function; if you want to evaluate a probability distribution function, this value should be "FALSE."

3. Press the "Enter" key to evaluate the function.

Tips & Warnings

• If you enter a non-numeric value for "alpha" or "beta," you will receive a "#VALUE" error.

• You will receive a "#NUM" error when the value for "x" is less than zero, as well as when the value for "alpha" or "beta" is less, or equal to zero.

References

• Microsoft: Weibull
• University of Alabama at Huntsville: Weibull, Wallodi