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By Professor Omar Hasan Kasule Sr.

Learning Objectives:

Analysis of proportions using approximate and exact methods


Key Words and Terms:

Analysis, analysis of 2 proportions

Analysis, binary data analysis

Analysis, categorical data analysis

Analysis, discrete data analysis

Chi-square, Pearson chi-square statistic of association

Table , contingency table


Inference on discrete data uses an approximate method (the chi-square) used for large samples and one exact method (Fisher's Exact Method) used for small samples.


Approximate methods are accurate for large samples and are inaccurate for small samples.


The data is laid out in contingency tables and is inspected manually before application of statistical tests.


The Pearson chi square is computed easily by most computer statistical programs. The computer also gives the p-value corresponding to the chi-square. Statisticians interpret the p-value to decide whether there is a statistically significant difference or a significant association between 2 groups being compared.

Professor Omar Hasan Kasule Sr. August 2005