GAMMA.DIST in Collabora Office: Separate Gamma Shape, Scale and Probability
Use Collabora GAMMA.DIST with explicit shape and scale, compare cumulative probabilities and densities, and verify an integer-shape model.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
Quick answer: =GAMMA.DIST(4;2;2;1) has independently expected result approximately 0.593994150. It evaluates cumulative probability at four for shape two and scale two.
Syntax and parameter meanings
=GAMMA.DIST(Number; Alpha; Beta; Cumulative)
Number is the nonnegative evaluation point. Alpha is the positive shape parameter, and Beta is the positive scale parameter. The dedicated Collabora help names the parameters without explaining their roles; the current Collabora interpreter source explicitly labels Alpha as shape and Beta as scale. Its separate evidence scope is stated below.
Cumulative is required for this dotted function. Zero or FALSE selects density; the help specifies one, TRUE or any other value for cumulative probability. Use explicit zero or one rather than depending on a nonstandard truthy value.
Scale has the same units as Number. It is not the rate: a rate parameter, when used by another mathematical reference, is the reciprocal of scale. The ordinary gamma model has mean AlphaBeta and variance AlphaBeta^2.
Example 1: build a shape-two table
Put 0, 2, 4, 6, 8 in A2:A6. Put 2 in F2 for shape and 2 in F3 for scale. Enter =GAMMA.DIST(A2;$F$2;$F$3;1) in B2 and fill down.
Independent cumulative targets are approximately 0, 0.264241118, 0.593994150, 0.800851727 and 0.908421806. The distribution mean is four, but its cumulative value at four is not 0.5; a mean is not necessarily a median.
For shape two and scale two, the independent cumulative formula is 1-EXP(-x/2)*(1+x/2). In C2 use =1-EXP(-A2/2)*(1+A2/2) and fill down. This provides a simple closed-form check for the chosen parameters.
Example 2: compare density and a probability band
Use =GAMMA.DIST(A2;$F$2;$F$3;0) in D2. At x=2, 4 and 6, the independent densities are approximately 0.183939721, 0.135335283 and 0.074680603 per original unit.
The probability between two and six is the difference of cumulative values: =GAMMA.DIST(6;2;2;1)-GAMMA.DIST(2;2;2;1), independently approximately 0.536610609. Subtracting the two density values would not give that probability.
The survival probability beyond eight is =1-GAMMA.DIST(8;2;2;1), independently approximately 0.091578194. Keep the event description beside the formula so a tail is not mistaken for the accumulated probability below its threshold.
Advanced application: model a sum of exponential waits
A gamma distribution with integer shape two and scale two is the distribution of the sum of two independent exponential waits, each with mean two. Its mean is four and variance eight.
This interpretation requires independent waits with the same scale. It does not apply automatically to two arbitrary observed durations. The function evaluates chosen parameters; it does not test the assumptions or fit a process model.
With Alpha=1, the gamma distribution reduces to an exponential distribution with rate 1/Beta. Thus GAMMA.DIST(3;1;2;1) has the same independent target as EXPON.DIST(3;0.5;1), approximately 0.776869840.
Advanced application: check an inverse quantile
=GAMMA.INV(0.9;2;2) has independently expected result approximately 7.779440340. Passing the full stored result into GAMMA.DIST with the same parameters and cumulative flag one should target 0.9.
The help calls GAMMA.DIST similar to GAMMADIST and introduced for interoperability, without dating the introduction. Do not infer an omitted-argument default from a legacy spelling: this page follows the documented four-argument dotted syntax.
Errors and troubleshooting
Use positive shape and scale and nonnegative evaluation points. Density behavior at zero depends on shape, so the zero-density shape-two example is not a universal endpoint rule. Invalid-input displays and extreme-tail accuracy remain unverified natively.
Check whether a rate was mistakenly supplied as Beta, whether the cumulative flag was omitted, and whether units match. A density is not a probability at an exact continuous value, even when both outputs happen to be below one.
Availability and verification
The exact function is documented in Collabora Office 26.04 desktop help. The snapshot was retrieved on 2026-10-13 and hash-verified on October 15, 2026. Desktop help is not proof of Online or mobile availability. First introduced release and last functioning version are unknown; the dedicated source does not establish them.
No native Collabora or WPS execution occurred. Numerical values are independent mathematical expectations, not certification of application errors or all numerical limits. Formulas use English names and semicolon separators.
A current Collabora interpreter source snapshot retrieved October 15, 2026 corroborates the described domain or parameter roles. It is from the moving main branch, not a pinned 26.04 binary, and is not an application execution.
The dedicated help identifies namespace COM.MICROSOFT.GAMMA.DIST and places the function outside the cited OpenFormula 1.3 standard. This format disclosure does not establish cross-product behavioral identity.