© 1973 by Biometrika Trust
Approaches to the null distribution of
b1
1Boston University
2Los Alamos Scientific Laboratory
A comparative study of approximations to the null distribution of
b1 is given for small sample sizes, i. e. n
35. The approximations studied are the approximations by the normal distribution, the Johnson SU distributions, the t or Pearson Type VII distributions, the Cornish-Fisher expansions using moments up to the eighth, with and without Geary's adjustment, and, finally, Monte-Carlo simulations. For the usual levels of significance all the approximations, except the normal approximation, appear satisfactory for n
8. Because the SU and t distributions allow approximations to the probability integrals, they can be used to combine the results of independently drawn samples.
Key Words: Tests of normality Measure of skewness Johnson's approximation t approximation Pearson curves approximation Cornish-Fisher expansions Simulation Monte-Carlo procedure