sample vs. population proportion using a z-score in excel
Hi,
First I would look at Excel's z-test option. To run this you need the
Analysis ToolPak attached - choose Tools, Add-ins, and check Analysis
ToolPak. Then choose Tools, Data Analysis, and scroll the list to the last
option z-test Two Sample for Means and click OK. See it this does what you
need.
Second, look at the ZTEST function and see if this does what you need.
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Thanks,
Shane Devenshire
"Christopher" wrote:
To all,
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!
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