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The Math: SurveyStat

SurveyStat provides standard statistical testing for survey data, including T-Tests for means and Z-Tests for proportions.

Significance Testing

We use two-tailed tests at the 95% confidence level (p < 0.05) by default.

1. Z-Test for Proportions

Used when comparing percentages (e.g., Top 2 Box scores) between two independent groups.

Z = (p1 - p2) / √[ p(1-p)(1/n1 + 1/n2) ]

Where p is the pooled proportion.

2. T-Test for Means

Used when comparing average scores (e.g., 5-point scale means) between two independent groups. We assume unequal variances (Welch's t-test).