# Another p-value-am I missing anything?

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• Dec 14th 2009, 09:37 PM
yvonnehr
Another p-value-am I missing anything?
I can't figure out how to solve this one. Am I missing data or how should I go about it?

Problem 2.
An automatic bottling machine fills cola into two liter (2000 cc) bottles. A consumer advocate wants to test the null hypothesis that the average amount filled by the machine into a bottle is at least 2000 cc. A random sample of 40 bottles coming out of the machine was selected and the exact content of the selected bottles are recorded. The sample mean was 1999.6 cc. The population standard deviation is known from past experiences to be 1.30 cc. Compute the p-value for this test. Test the null hypothesis at the 5% significance level. Test the null hypothesis at the 1% significance level.

Solution in progress...
Data:
$\mu=2000 cc, n=40, \overline{x}=1999.6, \sigma=1.30 cc$

$\alpha_1=.05 \rightarrow Z_1=1.96.$ If $-1.96 < Z* < 1.96$, then we fail to reject the null hypothesis.

$\alpha_2=.01 \rightarrow Z_2=2.575.$ If $-2.575 < Z* < 2.575$, then we fail to reject the null hypothesis.

$H_0: ?$
$H_a: ?$

$Z*=\frac{\hat{p}-p_o}{\sqrt{\frac{p_o(1-p_o)}{n}}}$, but what is $\hat{p}$ and $p_o$ for this problem?
• Dec 14th 2009, 10:33 PM
matheagle
you are testing means, not proportions.
(back to grading)
• Dec 14th 2009, 10:41 PM
yvonnehr
thanks!
Quote:

Originally Posted by matheagle
you are testing means, not proportions.
(back to grading)

I just realized that my teacher, who's name will remain anonymous, was referring to proportions as p-values. That's why I was so very confused!

Thanks for the note. Take it easy on the students. ;-)