How to use the GAMMA.DIST function
How to use the GAMMA.DIST function?
The GAMMA.DIST function calculates the gamma often used in queuing analysis (probability statistics) that may have a skewed distribution. This function was introduced in Excel 2010 and has replaced the GAMMADIST function.
What is a gamma distribution?
The gamma distribution is a two-parameter continuous probability distribution defined for positive values. It generalizes other distributions like chi-square and exponential and models positively skewed data like time durations.
What is queuing analysis in probability statistics?
Queuing analysis involves using probability and statistics to analyze and model queues (waiting lines). Studies arrival patterns, service times, queue capacity to describe performance and uses probability distributions like Poisson and exponential distributions. It calculates key metrics like expected wait times, queue lengths, utilization.
What is a skewed distribution?
Skewness and asymmetric tails describe the lack of balance and symmetry in probability distributions and datasets. Identifying skewness is fundamental in statistics.
Positive skewness implies a group of values with an asymmetric tail moving toward more positive values. Negative skewness implies a group of values with an asymmetric tail moving toward more negative values.
What is an asymmetric tail?
A symmetric distribution like the normal distribution has no skewness. An asymmetric tail is when one tail of the distribution extends further than the other.
GAMMA.DIST function example
Formula in cell C7:
GAMMA.DIST function Syntax
GAMMA.DIST(x,alpha,beta,cumulative)
GAMMA.DIST function Arguments
| x | Required. |
| alpha | Required. |
| beta | Required. 1 returns the standard gamma distribution. |
| cumulative | Required. A boolean value. TRUE - cumulative distribution function FALSE - probability density function |
What is a density function?
A density function in statistics describes the relative likelihood that a random variable takes on a given value. The area under the entire density function integrates to 1.
There are two main types of density functions:
- Probability Density Function (PDF)
PDFs are used for continuous random variables and provides the probability that the variable's value lies within a small range around x.
The area under PDF over an interval provides the probability that the variable lies within that interval. - Probability Mass Function (PMF)
PMFs are used for discrete random variables and gives the exact probability that a variable takes on a specific value x.
GAMMA.DIST function not working
The GAMMA.DIST function returns
- #VALUE! error value if alpha, beta or x is non-numeric.
- #NUM! error value if:
- x < 0 (zero)
- alpha <= 0 (zero)
- beta <= 0 (zero)
How is the GAMMA.DIST function calculated?
The equation to calculate the gamma probabiltiy density function:
The standard gamma probability function:
Functions in 'Statistical' category
The GAMMA.DIST function function is one of many functions in the 'Statistical' category.
How to comment
How to add a formula to your comment
<code>Insert your formula here.</code>
Convert less than and larger than signs
Use html character entities instead of less than and larger than signs.
< becomes < and > becomes >
How to add VBA code to your comment
[vb 1="vbnet" language=","]
Put your VBA code here.
[/vb]
How to add a picture to your comment:
Upload picture to postimage.org or imgur
Paste image link to your comment.
Contact Oscar
You can contact me through this contact form