[−][src]Trait test::stats::Stats
test
)Trait that provides simple descriptive statistics on a univariate set of numeric samples.
Required methods
fn sum(&self) -> f64
test
)Sum of the samples.
Note: this method sacrifices performance at the altar of accuracy Depends on IEEE-754 arithmetic guarantees. See proof of correctness at: "Adaptive Precision Floating-Point Arithmetic and Fast Robust Geometric Predicates"
fn min(&self) -> f64
test
)Minimum value of the samples.
fn max(&self) -> f64
test
)Maximum value of the samples.
fn mean(&self) -> f64
test
)Arithmetic mean (average) of the samples: sum divided by sample-count.
fn median(&self) -> f64
test
)Median of the samples: value separating the lower half of the samples from the higher half.
Equal to self.percentile(50.0)
.
fn var(&self) -> f64
test
)Variance of the samples: bias-corrected mean of the squares of the differences of each
sample from the sample mean. Note that this calculates the sample variance rather than the
population variance, which is assumed to be unknown. It therefore corrects the (n-1)/n
bias that would appear if we calculated a population variance, by dividing by (n-1)
rather
than n
.
fn std_dev(&self) -> f64
test
)Standard deviation: the square root of the sample variance.
Note: this is not a robust statistic for non-normal distributions. Prefer the
median_abs_dev
for unknown distributions.
fn std_dev_pct(&self) -> f64
test
)Standard deviation as a percent of the mean value. See std_dev
and mean
.
Note: this is not a robust statistic for non-normal distributions. Prefer the
median_abs_dev_pct
for unknown distributions.
fn median_abs_dev(&self) -> f64
test
)Scaled median of the absolute deviations of each sample from the sample median. This is a
robust (distribution-agnostic) estimator of sample variability. Use this in preference to
std_dev
if you cannot assume your sample is normally distributed. Note that this is scaled
by the constant 1.4826
to allow its use as a consistent estimator for the standard
deviation.
fn median_abs_dev_pct(&self) -> f64
test
)Median absolute deviation as a percent of the median. See median_abs_dev
and median
.
fn percentile(&self, pct: f64) -> f64
test
)Percentile: the value below which pct
percent of the values in self
fall. For example,
percentile(95.0) will return the value v
such that 95% of the samples s
in self
satisfy s <= v
.
Calculated by linear interpolation between closest ranks.
fn quartiles(&self) -> (f64, f64, f64)
test
)Quartiles of the sample: three values that divide the sample into four equal groups, each
with 1/4 of the data. The middle value is the median. See median
and percentile
. This
function may calculate the 3 quartiles more efficiently than 3 calls to percentile
, but
is otherwise equivalent.
See also: https://en.wikipedia.org/wiki/Quartile
fn iqr(&self) -> f64
test
)Inter-quartile range: the difference between the 25th percentile (1st quartile) and the 75th
percentile (3rd quartile). See quartiles
.