xref: /freebsd/usr.bin/ministat/README (revision 97759ccc715c4b365432c16d763c50eecfcb1100)
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2A small tool to do the statistics legwork on benchmarks etc.
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4Prepare your data into two files, one number per line
5run
6	./ministat data_before data_after
7
8and see what it says.
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10You need at least three data points in each data set, but the more
11you have the better your result generally gets.
12
13Here are two typical outputs:
14
15x _1
16+ _2
17+--------------------------------------------------------------------------+
18|x            +    x+      x            x   x             +           ++   |
19|        |_________|______AM_______________|__A___________M_______________||
20+--------------------------------------------------------------------------+
21    N           Min           Max        Median           Avg        Stddev
22x   5         36060         36138         36107       36105.6     31.165686
23+   5         36084         36187         36163       36142.6     49.952978
24No difference proven at 95.0% confidence
25
26Here nothing can be concluded from the numbers.  It _may_ be possible to
27prove something if many more measurements are made, but with only five
28measurements, nothing is proven.
29
30
31x _1
32+ _2
33+--------------------------------------------------------------------------+
34|                                                               +          |
35|                               x                               +         +|
36|x                    x         x          x                    +         +|
37|         |_______________A_____M_________|                   |_M___A____| |
38+--------------------------------------------------------------------------+
39    N           Min           Max        Median           Avg        Stddev
40x   5         0.133         0.137         0.136        0.1354  0.0015165751
41+   5         0.139          0.14         0.139        0.1394 0.00054772256
42Difference at 95.0% confidence
43        0.004 +/- 0.00166288
44        2.95421% +/- 1.22812%
45        (Student's t, pooled s = 0.00114018)
46
47Here we have a clearcut difference, not very big, but clear and unambiguous.
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