If 15 observations are taken independently from a chi-square distribution with 15 degrees of freedom, find the probability that at least two of the sample items exceed 8.547.

Can anyone help with this?

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- December 17th 2008, 03:40 AMPatriots326Chi-square distribution
If 15 observations are taken independently from a chi-square distribution with 15 degrees of freedom, find the probability that at least two of the sample items exceed 8.547.

Can anyone help with this? - December 17th 2008, 12:53 PMmeymathis
Let be a random variable with distribution . A success is when . Now repeat 15 times (each trial is independent), denoting the trial as .

(i.e. the probabilities of success) are constant with respect to . In other words, you have 15 independent trials, success is constant ( ), and you are asked what is the probability of at least 2 successes. This smells like a binomial distribution if you let be the number of successes.

You use the distribution only to calculate .

(from table)

Make sense? - December 18th 2008, 07:43 AMPatriots326
Yea a little bit, I see if I can figure it out and if not, I can show you what I've done. Then we can figure it out.