stats [-[no]parallel] [-qapprox|-qexact] [<item> ...]
Calculates statistics on the data in the table. This filter turns the table sideways, so that each row of the output corresponds to a column of the input. The columns of the output table contain statistical items such as mean, standard deviation etc corresponding to each column of the input table.
By default the output table contains columns for the following items:
Name: Column name
StDev: Population Standard deviation
Minimum: Numeric minimum
Maximum: Numeric maximum
NGood: Number of non-blank cells
However, the output may be customised by supplying one or more
<item> headings. These may be selected
from the above as well as the following:
NBad: Number of blank cells
Variance: Population Variance
SampStDev: Sample Standard Deviation
SampVariance: Sample Variance
MedAbsDev: Median Absolute Deviation
ScMedAbsDev: Median Absolute Deviation * 1.4826
Skew: Gamma 1 skewness measure
Kurtosis: Gamma 2 peakedness measure
Sum: Sum of values
MinPos: Row index of numeric minimum
MaxPos: Row index of numeric maximum
Cardinality: Number of distinct values in column; values >100 ignored
Median: Middle value in sequence
Quartile1: First quartile
Quartile2: Second quartile
Quartile3: Third quartile
ArrayNGood: Per-element non-blank counts for fixed-length array columns
ArraySum: Per-element sums for fixed-length array columns
ArrayMean: Per-element means for fixed-length array columns
ArrayStDev: Per-element population standard deviation for fixed-length array columns
Q.25: First quartile
Q.625: Fifth octile
Any parameters of the input table are propagated to the output one.
flag controls how quantiles are calculated.
-qexact they are calculated exactly,
but this requires memory usage scaling with the number of rows.
-qapprox flag is supplied,
an method is used which is typically slower and produces only
approximate values, but which will work in fixed memory
and so can be used for arbitrarily large tables.
By default, exact calculation is used.
These flags are ignored if neither quantiles nor the MAD
are being calculated
-noparallel flag may be supplied to inhibit
multi-threaded statistics accumulation.
Calculation is done in parallel by default if multi-threaded
hardware is available, and it's usually faster.