Two-Sample Z-test Output

Applied Statistics Handbook
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Software Output

Summary data from the previous example

Two-Sample Difference of Proportions (2-tailed)

School A School B

Sample Proportion 0.23 0.07

Sample Size (n) 80 180

Z-statistic p <

Significance 3.674 0.0002

Interpretation

For a 2-tailed test, the p-value represents the probability of making a type 1 error (concluding there is statistical significance when there is none). Since there is far less than a 5% chance of making a type 1 error, you would conclude there is statistical significance.