Calculation form 2 for χ2 distribution. Dr.Funatsu, Professor of Meisei university, Tokyo.　EMail　Contents of forms　Top page
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[Input]
Degree of freedom n=
C is the area of right side of the distribution and 0.0001≦C.
Upper bound of C is 0.9 for n=1, 0.99 for n=2 and 1 for n>2.
E is an index of calculation errors
and 0.0001≦E≦0.01
C= E=
[Output]
Value of calculation C=
Value of calculation E=
Value of b=

No calculation of a here.

When probability is very small, it may be shown in index style like 3.14e-12. Be careful of last place of decimals.

C and b are fixed in the image below, irrespective of input value of C in the left column.
n=


............................................................To seek related probabilities for given a and b. 

Calculation errors of b  Errors vary by E. The smaller E is, the smaller become the errors.
Following tables are values for reference.
 
Degree of freedom n=1 and C=0.05(decimals not rounded） 
          　　       E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   3.84       3.841        3.8415      3.841　　

Degree of freedom n=2 and C=0.05(decimals not rounded）
   　　              E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   5.99       5.991        5.9915      5.991　　

Degree of freedom n=5 and C=0.05(decimals not rounded）
          　　       E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   11.07      11.07        11.0705     11.070　　

Degree of freedom n=1 and C=0.02(decimals not rounded）
  　　               E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   5.41       5.412        5.4119      5.412　　

Degree of freedom n=2 and C=0.02(decimals not rounded）
  　　               E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   7.82       7.824        7.824       7.824　　

Degree of freedom n=5 and C=0.02(decimals not rounded）
   　　              E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   13.39      13.388       13.3882     13.388　　

Degree of freedom n=1 and C=0.01(decimals not rounded）
   　　              E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   6.63       6.635        6.6349      6.635　　

Degree of freedom n=2 and C=0.01(decimals not rounded）
 　　                E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   9.21       9.210        9.2103      9.210　　

Degree of freedom n=5 and C=0.01(decimals not rounded）
   　　              E=0.01     E=0.001      E=0.0001    Known value
Shown value of b　   15.09      15.086        15.0863    15.086