TDIST Function (Calligra Sheets)

• Introduced: First release not established; the name is present in Calligra 2.4.0 source.
• Supported in: Calligra Sheets 26.08.2, with no retirement established.
• Scope: Desktop Sheets with the Statistical module. Examples use English semicolon-separated formulas.
• Checked: October 14, 2026. Selected formulas ran through the official 25.04.2 engine library. Source and independent mathematics were checked. This is engine evidence, with no GUI-cell or import verification; 26.08.2 was source-checked only.

For nonnegative x, TDIST(x,ν,1) returns the upper-tail Student t probability and tails=2 returns twice that value, corresponding to P(|T|≥x). Degrees of freedom ν control the distribution shape. The implementation accepts fractional degrees of freedom at or above one. Function help.

=TDIST(x;degreesFreedom;tails)

All three arguments are required. Degrees of freedom must be at least 1. The tails argument is converted to an integer and must then be 1 or 2; 1.9 selects one tail in the tested call. Registration and implementation.

The engine and mathematical columns are separate. Results are rounded to twelve decimal places, or thirteen significant digits in scientific notation for very small or large values. This is a display choice, not an accuracy guarantee. NaN and infinity are nonfinite outputs; an engine error flag is checked separately from those values.

For a pre-specified two-sided Student t comparison with |t|=2 and ν=10, the mathematical tail probability is approximately 0.073388034770. One tail at the positive cutoff is half of that. The engine’s nearby approximation is shown separately. The degrees of freedom and whether the test is one- or two-sided must come from the statistical design, not from whichever result looks favorable.

If your signed statistic is −2, the implementation still uses its magnitude. It does not return the signed upper tail P(T≥−2), which is close to 0.963305982615 mathematically.

For ν=1, Student t is the standard Cauchy distribution. Its upper-tail probability at x=1 is exactly 0.25, and the two-tail probability is 0.5. The small residual in the engine rows comes from its approximate beta helper.

At zero, one tail is 0.5 and two tails total 1. The executed identity below checks that the two-tail output is twice the one-tail output at x=2,ν=10. This shared-computation identity is separate from independent accuracy of either tail.

The executed advanced check was:

=TDIST(2;10;2)-2*TDIST(2;10;1)

Its engine result was 0.

Tails outside the converted values 1 or 2, degrees of freedom below one, and wrong argument counts yield #VALUE!. Malformed x text becomes zero in the selected engine call and returns a full two-tail probability. Do not feed signed statistics into a directional inference without first resolving the intended tail convention.

• Function-specific implementation
• Versioned function help
• Beta helper
• Conversion helper

The statistical module and value-calculation helpers are byte-identical between the inspected 25.04.2 and 26.08.2 sources. That comparison supports the source discussion but does not establish later-version native output, every locale or arbitrary extreme-parameter accuracy.

NORMSDIST.