I used my calculator to do a two tailed Z test for two proportions. Here's the data I input:
X1 is 834 n1 is 3610 X2 is 145 n2 is 495
I chose p1 not equal to p2
I set alpha to 0.05
My hypotheses are:
$H_0: \pi_1= \pi_2$
$H_a: \pi_1 \neq \pi_2$
The calculated Z score is $-3.03$, which gives a $p = .002$, so I am rejecting the null.
Here is my question: what does the negative Z score mean:
a) that the $X_1/n_1$ proportion is > than the $X_2/n_2$ proportion? OR
b) that the $X_2/n_2$ proportion is > than the $x_1/n_1$ proportion?