 Zaheer Formulas ,

In the probability theory and stat, gamma distribution is two parameter family of continue probability distributions. This has scale parameter ? and the shape parameter k. When k is integer, then distribution represents Erlang distribution that is the sum of the K independent exponential distributed random variable, each of it has means of ? which is the equivalent to rate parameter of ?-1.

Gamma distribution is usually the probability model for waiting time, for example: life testing, waiting time till death is random variables that are usually modeled with gamma distribution. It’s the maximum entropy probability distributions for the random variate X for that E (X) = A is the fixed and greater than 0 and the E (ln (X) = ? (a) is fixed.

Excel Gammadist distribution returns Gamma Distribution, which’s usually used to provide probabilities for the values which could contain skewed distribution, like queuing analysis. The user can tell whether the probability density or the cumulative distribution function must be used.

Where the arguments are:

• x – refers to the value which you like to evaluate the function (should be ? 0)
• Alpha – the parameter of distribution
• Beta – parameter of distribution

Note: when the beta is equals to zero, and then it specifies the standard Gamma distribution

• Cumulative – logical argument which tells the kind of gamma distribution to be computed. It can have values of true or false, which means:

True – compute the cumulative distributions function

False – compute probability density function

How to Use Gammadist Function in Excel?

Excel is an influential spreadsheet application which lets the person compile and calculate large amounts of numerical data with a simple click of a button. Example of this is the Excel’s GAMMADIST function. In case you have required statistical knowledge, then you can use the Excel’s GAMMADIST function and look for the skewed distribution of variables set.

Steps:

• Activate Excel spreadsheet application, and then choose Start. Choose Programs or all programs from start menu. Then opt for Microsoft Office in the menu options. Finally choose Excel from the office menu to run the spreadsheet
• Open spreadsheet file that contains data that you like to use in Excel Gammadist function. Hit File options from the main Excel Menu. Then opt for Open from files menu and look for the spreadsheet file. Finally, double click the file and open.
• Pick the cell within the spreadsheet where you like to out the output from Gammadist Function.
• Click on Insert Function situated above the column heading in the spreadsheet. The function dialogue must appear once you hit the button.
• Type the Gammadist in the search box situated on top of dialogue box. And then, double click in the Gammadist function to run the Gammadist dialogue box.
• Input values of x, alpha and Beta along with the Cumulative logic value. Once you put the values, hit OK and output of Gammadist function would be shown in the cells you chosen in Step3.