abstract:Preface: The Chi-Square distribution is the distribution of the sum of the squares of a set of normally distributed random variables. Its value stems from the fact that the sum of random variables from any distribution can be closely approximated by a normal distribution as the sum as samples size increases.
Care must betaken in theinterpretationof the chi-squaredtest, sinceit haslow power in the (common) situation of a meta-analysiswhen trials havesmallsample size or are few in number.