© 1980 by Biometrika Trust
An approximation to the distribution of the X2 goodness-of-fit statistic for use with small expectations
Department of Mathematics, Ahmadu Bello University Nigeria
Department of Mathematics, University of Essex
This paper is concerned with the X2 goodness-of-fit test when the observed frequencies are supposed to be distributed according to a specified multinomial distribution. We propose a log normal approximation to the distribution of X2. Our results suggest that the approximation is valid providing that the smallest expectation is greater than r/d
, where r is the number of expectations less than 5, and d is the number of degrees of freedom.
Key Words: Chi-squared distribution Chi-squared goodness-of-fit test Log normal distribution Small expectation.