# Math Help - Chi squared?

1. ## Chi squared?

Hi,

This is the first chi sqaured test that i have done since ive been taught about it in a lecture. The lecturer isnt that good and neither is the notes that he has given out, so im a little unsure about something.

I have done a chi squared test on some data that has 9 degrees of freedom. The chi sqaured value that i get once ive added all the values together is 93.4. Looking at the chi sqaured table, i cant see any values near this value. So which do i choose?

Many thanks to anyone that can help me with this

Rob

2. Originally Posted by Shocker
Hi,

This is the first chi sqaured test that i have done since ive been taught about it in a lecture. The lecturer isnt that good and neither is the notes that he has given out, so im a little unsure about something.

I have done a chi squared test on some data that has 9 degrees of freedom. The chi sqaured value that i get once ive added all the values together is 93.4. Looking at the chi sqaured table, i cant see any values near this value. So which do i choose?

Many thanks to anyone that can help me with this

Rob
Rob,

You should not be looking for a number near your test statistic; rather, you want the critical value for the chi square test.

In addition to the number of degrees of freedom, you also need a significance level for the test.

If the desired significance level is 0.95, for example, in my table of the chi square distribution I find 16.9 as the critical value of the test statistic with 9 degrees of freedom. Since 93.4 is greater than 16.9, the conclusion of the test would be to reject the null hypothesis.

3. Originally Posted by awkward
Rob,

You should not be looking for a number near your test statistic; rather, you want the critical value for the chi square test.

In addition to the number of degrees of freedom, you also need a significance level for the test.

If the desired significance level is 0.95, for example, in my table of the chi square distribution I find 16.9 as the critical value of the test statistic with 9 degrees of freedom. Since 93.4 is greater than 16.9, the conclusion of the test would be to reject the null hypothesis.
The critical value is the sum of the chi square test isnt it?

$X^2 = Sum ( ((O-E)^2) /E)$

4. Originally Posted by Shocker
The critical value is the sum of the chi square test isnt it?

$X^2 = Sum ( ((O-E)^2) /E)$
No, that is the test statistic.