Stats 0.3.0 tails - CyrilB1531/lodestar GitHub Wiki
Lodestar.Stats 0.3.0. This page is frozen at that release. Read the current documentation for what
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Distribution tails — Lodestar.Stats
One type, Distributions: the tail probabilities and the
quantile a caller holding its own statistic needs, without going through a hypothesis test to
reach them.
Why only four members
This package computes every tail it needs from its own log-gamma, incomplete beta and incomplete
gamma, and decisions/0081
kept that layer internal — deliberately, and with the condition for changing its mind written
down: "publishing later stays possible the day a second package needs the same functions."
Lodestar.Stats.Regression is that day. What it needs is a Student tail for each coefficient's
p-value, a Student quantile for each confidence interval, and an F tail for the overall test.
Those three are published. The log-gamma, the incomplete beta and gamma, the normal tail and the
finite-sample Kolmogorov distribution underneath them stay internal, because nothing has asked for
them and an unpublished API can still be published later — the reverse is not true.
What publishing cost
A parity promise of its own. The internal tests check these functions against closed forms,
which is enough for a p-value near 0.05 and says nothing about the far tail. The corpus behind
this page replays scipy.stats down to 3.1e-24, compared relatively: an absolute 1e-9
there would accept an implementation returning zero.
It also cost a correction. The internal helper behind
Distributions.StudentQuantile solves
P(T > x) = p and therefore carries the opposite sign to a quantile. Published under its own name
unchanged, it would have handed a caller -2.18 where every table prints +2.18.
Types
| Type | What it is |
|---|---|
Distributions |
Two Student tails and the F tail, for a caller holding its own statistic. |
See also
- Hypothesis tests — the ten families built on the same machinery.
- Python → C# equivalence.