Chi-squared test for homogeneity of a sample

Input Values

Undertake a chi-squared test for homogeneity on sample counts. The test calculates the expected counts assuming homogeneity (all classes have an equal probability) and undertakes a chi-squared test to test whether the observed values deviate significantly from the expected values.

Inputs are the desired level of confidence in the estimate, the desired precision of the results and two columns of data: The first column is a list of group identifiers and the second column is sample counts for each group. A header row should be included in the data and will be used to label the output.

Outputs include:

• a table of observed and expected counts, proportions and confidence limits;
• chi-squared statistic, degrees of freedom and corresponding P-value; and
• a plot of confidence limits for the proportions in each group.