STAT 111 Lecture Notes - Lecture 14: Mull, Null Hypothesis, Abortion-Rights Movements
Document Summary
Notes on z and c2 in 2 2 tables: z. Suppose that we have the following data: women men total pro-choice pro-life total o11 o21 o12 o22 r1(= x11 + x12) r2(= x21 + x22) c1(= x11 + x21) c2(= x12 + x22) n. In this table r1 and r2 are row totals, c1 and c2 are column totals and n, which equals both r1 + r2 and c1 + c2, is the grand total. The test statistic that we eventually use to test the null hypothesis against the alternative hypothesis is: z = (o11o22 o12o21) n. This is the expression (103) in the notes. To answer this question we go back to the original form of z, which is z = o11 r1 q (c1/n)(c2/n) r1 o21 r2. This is the expression (101) in the notes. The expressions (101) and (103) are identical: we use (103) only because it is computationally easier to deal with than (101).
