P-value 0f 0.926?

#1
Hi everyone,

I performed a chi-squared goodness of fit test with 11 degrees of freedom, but according to the answer the p value is 0.926!! Where is this value coming from as I looked under the table for values and I got a pvalue of 19.68?
 

TheEcologist

Global Moderator
#2
Hi everyone,

I performed a chi-squared goodness of fit test with 11 degrees of freedom, but according to the answer the p value is 0.926!! Where is this value coming from as I looked under the table for values and I got a pvalue of 19.68?
It is the probability of obtaining your chi-squared value or a more extreme value (under the chi-squared distribution). E.g. if your chi-squared value was 0, the p-value would be 1.

http://en.wikipedia.org/wiki/Chi-square_distribution

It is probably more helpful for you to review this first:

http://en.wikipedia.org/wiki/P-value

And then if you have questions, we will be more than happy to help you!
 

Mean Joe

TS Contributor
#3
Hi everyone,

I performed a chi-squared goodness of fit test with 11 degrees of freedom, but according to the answer the p value is 0.926!! Where is this value coming from as I looked under the table for values and I got a pvalue of 19.68?
A p-value is supposed to be between 0 and 1; so 0.926 is a valid (not saying correct as I don't know your data) p-value, while 19.68 is not.

With 11 df, 19.68 is the critical value for a chi-square test at level alpha=.05.

If your X^2 is greater than 19.68, then you reject H[0]; else you accept it.
If your p-value is less than .05, then you reject H[0]; else you accept it.