Let n independent trials of an experiment be such that 
are the respective numbers of times that the experiment ends in the mutually exclusive and exhaustive event
is constant throughout the n trials, then the probability of that particular sequence of trials is 
Theorem 6.5.1 says that the right-hand member of this last equation defines a statistic that has an approximate chi-square distribution with k − 1 degrees of freedom. Note that
Theorem 6.5.1
