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Values of chi squared?

Posted 9 years ago

While reviewing some problems of statistics that I have already solved, I did the following questions, in a section on contingency tables call chi-square table to know if we reject the null hypothesis or not.Then call tables to obtain the value corresponding to

\!
\*SubsuperscriptBox[\(\[Chi]\), \(0.05, 3\), \(2\)]

which is 7.815, my doubt is can be calculated that value in mathematica? thanks in advance

POSTED BY: Luis Ledesma
5 Replies

Jim thank you very much. I actually refreshed and after changing the code it worked. Also appreciate the Mathematica code that works too!

POSTED BY: Jim Collista

Does this work with any significance level or just 0.05? Got the same results when changed alpha to 0.01, probably doing something wrong. I am also trying to replicate this calculator in Mathematica, but keep getting an error with degree of freedom calculation.

POSTED BY: Jim Collista
Posted 2 years ago

I get the appropriate values:

df = 3;

alpha = 0.01;
InverseCDF[ChiSquareDistribution[df], 1 - alpha]
(* 11.34486673014437` *)

alpha = 0.05;
InverseCDF[ChiSquareDistribution[df], 1 - alpha]
(* 7.814727903251181` *)

Also, there are many, many ways to mimic the calculator you reference. Here's one way:

Manipulate[
 InverseCDF[ChiSquareDistribution[df], 1 - \[Alpha]], 
 {{\[Alpha], 3}, {0.001, 0.005, 0.01, 0.05}},
 {{df, 1}, 1, 120, 1, Appearance -> "Labeled"}]

Chisquare calculator

POSTED BY: Jim Baldwin
Posted 9 years ago

Thank you Jim for your help to solve my question, is exactly what I needed,

POSTED BY: Luis Ledesma
Posted 9 years ago

If you look up "chisquare distribution" in the Wolfram Documentation center you'll find the necessary functions.

In[6]:= alpha = 0.05
df = 3
InverseCDF[ChiSquareDistribution[df], 1 - alpha]

Out[6]= 0.05

Out[7]= 3

Out[8]= 7.81473
POSTED BY: Jim Baldwin
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