C

#### Christopher

Needed some help on finding a formula to use in excel to calculate a z-

score that is comparing a sample proportion to a population

proportion. Here's the data:

Sample proportion = 0.31

N = 998

Population proportion = 0.49

I can find a z-score using a formula by hand: (z-score = -11.39), but

wanted to calculate in excel for many other variables. This is the

formula I used by hand:

p = sample proportion

Po = population proportion

alpha = 0.05 (z-critical = plus/minus 1.96)

non-directional test

z = (p-Po)/square root((Po(1-Po))/N)

When I use the standardize function in excel it gives me = -0.1153.

Any suggestions?

Thanks!