ministat
—
statistics utility
ministat |
[ -Ans ]
[-C
column ]
[-c
confidence_level ]
[-d
delimiter ]
[]
[file ... ] |
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:
-A
- Just report the statistics of the input and relative comparisons, suppress
the ASCII-art plot.
-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. The default is the terminal width,
or 74 if standard output is not a terminal.
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.
Any mathematics text on basic statistics, for instances Larry Gonicks excellent
"Cartoon Guide to Statistics" which supplied the above example.
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.