NAME¶
ministat —
statistics utility
SYNOPSIS¶
ministat |
[-ns]
[-C
column]
[-c
confidence_level]
[-d
delimiter]
[-w
[width]]
[file ...] |
DESCRIPTION¶
The
ministat command calculates fundamental statistical
properties of numeric data in the specified files or, if no file is specified,
standard input.
The options are as follows:
- -n
- Just report the raw statistics of the input, suppress the
ASCII-art plot and the relative comparisons.
- -s
- Print the average/median/stddev bars on separate lines in
the ASCII-art plot, to avoid overlap.
- -C
column
- Specify which column of data to use. By default the first
column in the input file(s) are used.
- -c
confidence_level
- Specify desired confidence level for Student's T analysis.
Possible values are 80, 90, 95, 98, 99 and 99.5 %
- -d
delimiter
- Specifies the column delimiter characters, default is SPACE
and TAB. See strtok(3) for details.
- -w
width
- Width of ASCII-art plot in characters, default is 74.
A sample output could look like this:
$ ministat -s -w 60 iguana chameleon
x iguana
+ chameleon
+------------------------------------------------------------+
|x * x * + + x +|
| |________M______A_______________| |
| |________________M__A___________________| |
+------------------------------------------------------------+
N Min Max Median Avg Stddev
x 7 50 750 200 300 238.04761
+ 5 150 930 500 540 299.08193
No difference proven at 95.0% confidence
If
ministat tells you, as in the example above, that there is
no difference proven at 95% confidence, the two data sets you gave it are for
all statistical purposes identical.
You have the option of lowering your standards by specifying a lower confidence
level:
$ ministat -s -w 60 -c 80 iguana chameleon
x iguana
+ chameleon
+------------------------------------------------------------+
|x * x * + + x +|
| |________M______A_______________| |
| |________________M__A___________________| |
+------------------------------------------------------------+
N Min Max Median Avg Stddev
x 7 50 750 200 300 238.04761
+ 5 150 930 500 540 299.08193
Difference at 80.0% confidence
240 +/- 212.215
80% +/- 70.7384%
(Student's t, pooled s = 264.159)
But a lower standard does not make your data any better, and the example is only
included here to show the format of the output when a statistical difference
is proven according to Student's T method.
SEE ALSO¶
Any mathematics text on basic statistics, for instances Larry Gonicks excellent
"Cartoon Guide to Statistics" which supplied the above example.
HISTORY¶
The
ministat command was written by Poul-Henning Kamp out of
frustration over all the bogus benchmark claims made by people with no
understanding of the importance of uncertainty and statistics.
From
FreeBSD 5.2 it has lived in the source tree as a
developer tool, graduating to the installed system from
FreeBSD 8.0.