1. The problem statement, all variables and given/known data If 15 Observations are taken independently from a chi-square distribution with 4 degrees of freedom, find the probability that at most 3 of the 15 sample items exceed 7.779 2. Relevant equations 3. The attempt at a solution This problem should be quite simple. I find that in the back of my text that the chi square distribution of 7.779 is .9... but the answer is .9444... I am at a loss at why it is not exactly .9 and where to go from here. I would appreciate any help. Thanks.