R.PWEIBULL Function (Gnumeric)

• Introduced: First release not established; present in the retained 1.12.57 source.
• Supported in: Gnumeric 1.12.62; no retirement is established.
• Scope: Desktop Gnumeric with its Statistical Functions From R plugin. English comma-separated formulas are shown.
• Checked: October 14, 2026. Tables and the named advanced check use 1.12.57 ssconvert. Current 1.12.62 source was inspected; that release was not executed.

R.PWEIBULL returns the lower Weibull CDF by default. For positive x it is 1−EXP(−(x/scale)^shape). Upper-tail mode returns the survival probability EXP(−(x/scale)^shape), and log_p requests the log of the selected tail. Versioned function help.

=R.PWEIBULL(x,shape,scale[,lower_tail[,log_p]])

x, shape and scale are required; shape and scale must be positive. lower_tail defaults to TRUE and log_p to FALSE. Match x and scale units; the shape parameter is dimensionless.

Brackets mark optional arguments; do not type them. Current worksheet implementation.

These self-contained formulas were recalculated natively. Ordinary-domain results were checked against independent mathematics; source guards explain the boundary cases. Results are rounded to twelve decimal places, or thirteen significant digits for small nonzero values. This is presentation precision, not a universal accuracy guarantee.

With shape 2 and scale 3, the probability of a value at most 2 is approximately 0.358819611570. The probability of exceeding 2 is approximately 0.641180388430. Their sum is one, as checked below.

At x equal to scale, the CDF is 1−EXP(−1), approximately 0.632120558829, regardless of positive shape. Scale is therefore not generally the median. For an interval from 1 to 2, subtract those two lower CDF values.

The upper log-tail has the particularly simple expression −(x/scale)^shape. At x=2, shape 2 and scale 3, it is exactly −4/9 mathematically. The native value is approximately −0.444444444444.

Use the requested tail directly when a probability is very small rather than subtracting a rounded value from one. With shape 1, the CDF reduces to the exponential model with the same scale. These identities check the interpretation of the parameters, not a guarantee of all extreme-tail precision.

The saved advanced-check result for =R.PWEIBULL(2,2,3)+R.PWEIBULL(2,2,3,FALSE()) was 1.

At zero or negative x, the lower probability is zero and the upper probability is one. Their log forms are respectively negative infinity, displayed as #NUM!, and zero. This helper correctly selects the tail at the support boundary; do not transfer a boundary rule from another R.* function without checking it.

Nonpositive shape or scale gives #NUM!, including when x is at a boundary. Nonnumeric text gives #VALUE!, while empty F5 is treated as zero. Wrong arity gives #N/A. The table’s errors distinguish parameter validation from a requested logarithm of a zero probability.

F5 is genuinely empty, rather than a cell containing an empty string.

• Current worksheet callback
• Tested-version worksheet callback
• Current pweibull calculation
• Tested-version pweibull calculation
• Nonfinite worksheet-value handling
• Statistical Functions From R plugin declaration

The relevant complete worksheet callback and main calculation helper are unchanged between the inspected versions. That does not establish later-version numerical execution. Both stale and uncached SUM controls recalculated correctly. Native XML preserves the R.* identities. The secondary ODF export keeps these calls in the ORG.GNUMERIC namespace; it does not establish execution in another product. GUI entry, other locales and other spreadsheet products were not tested.

R.PEXP, WEIBULL, EXP.