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From: Steve on 10 Jul 2010 04:01
Hi,

Can someone show me how to get Mathematica to provide the areas to the
right of a given critical value of the Chi Square distribution ?

The table entries shown at http://www2.lv.psu.edu/jxm57/irp/chisquar.html
are what I need to compute.

For example, given 8 degrees of freedom and a probability value of
0.05 the result would be 15.51.

And given 5 degrees of freedom with probability 0.1 the result is
9.24.

How can I produce these results in Mathematica ?

Thanks so much.

From: Patrick Scheibe on 10 Jul 2010 06:32
Hi,

what about

FindRoot[CDF[ChiSquareDistribution[8], x] - 0.95, {x, 1}]

?

Cheers
Patrick

On Sat, 2010-07-10 at 04:01 -0400, Steve wrote:
> Hi,
>
> Can someone show me how to get Mathematica to provide the areas to the
> right of a given critical value of the Chi Square distribution ?
>
> The table entries shown at http://www2.lv.psu.edu/jxm57/irp/chisquar.html
> are what I need to compute.
>
> For example, given 8 degrees of freedom and a probability value of
> 0.05 the result would be 15.51.
>
> And given 5 degrees of freedom with probability 0.1 the result is
> 9.24.
>
> How can I produce these results in Mathematica ?
>
> Thanks so much.
>


From: Bob Hanlon on 11 Jul 2010 06:17

Or use Quantile

prob = {0.95, 0.90, 0.80, 0.70, 0.50,
0.30, 0.20, 0.10, 0.05, 0.01, 0.001};

TableForm[
Table[
NumberForm[
Quantile[
ChiSquareDistribution[df],
1 - p],
{4, 3}],
{df, 10}, {p, prob}],
TableHeadings -> {Range[10], prob},
TableAlignments -> Right]


Bob Hanlon

---- Patrick Scheibe <pscheibe(a)trm.uni-leipzig.de> wrote:

=============
Hi,

what about

FindRoot[CDF[ChiSquareDistribution[8], x] - 0.95, {x, 1}]

?

Cheers
Patrick

On Sat, 2010-07-10 at 04:01 -0400, Steve wrote:
> Hi,
>
> Can someone show me how to get Mathematica to provide the areas to the
> right of a given critical value of the Chi Square distribution ?
>
> The table entries shown at http://www2.lv.psu.edu/jxm57/irp/chisquar.html
> are what I need to compute.
>
> For example, given 8 degrees of freedom and a probability value of
> 0.05 the result would be 15.51.
>
> And given 5 degrees of freedom with probability 0.1 the result is
> 9.24.
>
> How can I produce these results in Mathematica ?
>
> Thanks so much.
>


From: Bill Rowe on 11 Jul 2010 06:19
On 7/10/10 at 4:01 AM, s123(a)epix.net (Steve) wrote:

>Can someone show me how to get Mathematica to provide the areas to
>the right of a given critical value of the Chi Square distribution ?

>The table entries shown at
>http://www2.lv.psu.edu/jxm57/irp/chisquar.html are what I need to
>compute.

>For example, given 8 degrees of freedom and a probability value of
>0.05 the result would be 15.51.

>And given 5 degrees of freedom with probability 0.1 the result is
>9.24.

>How can I produce these results in Mathematica ?

Use Quantile. For example,

In[3]:= Quantile[ChiSquareDistribution[8], .95]

Out[3]= 15.5073

In[5]:= Quantile[ChiSquareDistribution[5], .9]

Out[5]= 9.23636


From: Ray Koopman on 11 Jul 2010 06:20
On Jul 10, 1:01 am, Steve <s...(a)epix.net> wrote:
> Hi,
>
> Can someone show me how to get Mathematica to provide the areas to the
> right of a given critical value of the Chi Square distribution ?
>
> The table entries shown athttp://www2.lv.psu.edu/jxm57/irp/chisquar.html
> are what I need to compute.
>
> For example, given 8 degrees of freedom and a probability value of
> 0.05 the result would be 15.51.
>
> And given 5 degrees of freedom with probability 0.1 the result is
> 9.24.
>
> How can I produce these results in Mathematica ?
>
> Thanks so much.

In[1]:= {df = 8, p = .05, 2 InverseGammaRegularized[df/2, p]}

Out[1]= {8, 0.05, 15.5073}

In[2]:= {df = 5, p = .1, 2 InverseGammaRegularized[df/2, p]}

Out[2]= {5 ,0.1, 9.23636}

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