F.INV in Collabora Office: Find an F Left-Tail Quantile
Use Collabora F.INV to convert cumulative probabilities into F thresholds, preserve degree ordering and verify the forward probability.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
Quick answer: =F.INV(0.95;5;10) has independently expected result approximately 3.325834530. It is the threshold with 95% of the specified F distribution below it.
Syntax and cumulative interpretation
=F.INV(Number; DegreesFreedom1; DegreesFreedom2)
Number is a left-tail cumulative probability. DegreesFreedom1 is the numerator degree count and DegreesFreedom2 the denominator degree count. All three arguments are required. Use 0<p<1 and positive integer degrees for the finite examples below.
The output is a nonnegative F-scale threshold, not a probability or an observed ratio calculated from data. The function does not infer degrees of freedom, compute sample variances or establish the validity of a statistical test.
For a 5% upper-tail threshold, use Number=0.95 here. The alternative right-tail inverse F.INV.RT uses 0.05. Keep the probability convention in a cell label rather than relying solely on a remembered function name.
Example 1: use a closed-form two-by-two distribution
Put 0.05, 0.5 and 0.95 in A2:A4. Enter =F.INV(A2;2;2) in B2 and fill down. Independent targets are approximately 0.052631579, 1 and 19.
For these degree counts, the cumulative function is x/(1+x), whose inverse is p/(1-p). Put =A2/(1-A2) in C2 and fill down to verify the values mathematically.
The large spread between the fifth and ninety-fifth percentiles is a property of this distribution, not an arithmetic error. A quantile table need not be symmetric around its median.
Example 2: perform a forward round trip
In D2 enter =F.DIST(B2;2;2;1) and fill down. Independent targets are 0.05, 0.5 and 0.95, matching the probabilities in A.
Do not switch the final flag to zero: a density at a quantile is not the cumulative probability that defined it. Keep B’s full stored values for the check, especially near an endpoint where quantiles can change rapidly.
At B4=19, =F.DIST.RT(B4;2;2) instead targets 0.05. The left and right probability conventions remain complementary even though their inverse names look similar.
Advanced application: reproduce the official median
The dedicated example =F.INV(0.5;5;10) has independently expected result approximately 0.931933161. It is below one, unlike the median of the symmetric two-by-two case.
Use degrees five and ten in separate labeled parameter cells. Filling formulas with absolute references avoids accidentally shifting the numerator or denominator degree count while copying a probability table.
Advanced application: construct an upper-tail threshold explicitly
For numerator degrees five and denominator degrees ten, =F.INV(0.95;5;10) and =F.INV.RT(0.05;5;10) have the same independent target, approximately 3.325834530.
The shared threshold does not make the functions interchangeable at the same probability. F.INV(0.05;5;10) answers a lower-tail question. A copied probability label can therefore introduce a substantial error without producing an invalid formula.
For a reciprocal ratio, degrees must be exchanged along with the transformation. Mathematically the left-tail quantile at p with d1,d2 is the reciprocal of the left-tail quantile at 1-p with d2,d1. This identity is useful for cross-checking moderate inputs, but forming complements near one can lose precision.
Errors and troubleshooting
Enter 95% or 0.95 for the ninety-fifth percentile, not the bare number 95. Endpoint limits and the actual application’s endpoint errors are not certified by these interior controls.
Check that numerator and denominator degrees match the statistic’s construction. The dedicated help does not establish every fractional-degree conversion, maximum degree count or extreme-probability tolerance. A numerically correct threshold is not proof that the data meet the assumptions of an F-based test; that requires a separate statistical assessment.
Availability and verification
The exact function is documented in Collabora Office 26.04 desktop help. Its source snapshot was retrieved on 2026-10-13 and hash-verified on October 15, 2026. Desktop documentation does not establish Online or mobile support. First introduced release and last functioning version are unknown; the dedicated source does not establish them.
No native Collabora Office run occurred. All worked values are independent mathematical expectations, not verification of native error codes or every numerical limit. Formulas use English names and semicolon separators.
The help identifies namespace COM.MICROSOFT.F.INV and places the function outside the cited OpenFormula 1.3 standard. This format disclosure does not prove identical behavior in another product.