The GAMMA.INV function in Google Sheets is a statistical function that returns the inverse of the gamma cumulative distribution for a specified probability, alpha, and beta. This powerful function is useful in various fields, including finance and science, for analyzing data distributions and understanding the likelihood of different outcomes.

Syntax

GAMMA.INV(probability, alpha, beta)

• probability: A decimal value representing the probability at which the inverse is to be calculated.
• alpha: A positive parameter of the distribution that affects the shape.
• beta: A positive parameter of the distribution that also influences the shape.

Example #1

GAMMA.INV(0.5, 2, 2)

This function call determines the value of the gamma distribution at a probability of 0.5, with both alpha and beta set to 2. The result would be approximately 0.5.

Example #2

GAMMA.INV(0.75, 5, 3)

This call calculates the gamma inverse at a 75% probability with alpha set to 5 and beta set to 3, yielding a result of about 3.33.

Example #3

GAMMA.INV(0.9, 1, 2)

Here, the function finds the inverse of the gamma distribution for a probability of 0.9 with alpha as 1 and beta as 2, resulting in approximately 2.78.

Error handling

• NUM! This error occurs if ‘probability’ is not between 0 and 1, or if ‘alpha’ and ‘beta’ parameters are not positive.
• VALUE! This error signifies that the input parameters are of the wrong type, possibly text instead of numbers.

Conclusion

The GAMMA.INV function is a valuable tool for those working with statistical data in Google Sheets. By understanding its syntax and applying it correctly, users can effectively calculate gamma distributions and make informed decisions based on probability analyses. Whether you’re analyzing financial trends or scientific data, GAMMA.INV can enhance your data analysis capabilities.