Posted by PK on Tuesday, February 21, 2012 at 4:28pm.
The population standard deviation (σ) for a standardized achievement test that is normally distributed is 8.
a.) Calculate the standard error of the mean if you draw a random sample of 50 test scores. Show your work for full credit . . .
b.) Your sample mean is calculated to be 77. Compute the 95% confidence interval for the mean. Show your work!
c.) Interpret the meaning of the 95% confidence interval in one sentence.

statistics  MathGuru, Tuesday, February 21, 2012 at 4:49pm
Here are a few hints to get you started:
a). Standard error of the mean = standard deviation divided by the square root of the sample size
b). CI95 = mean ± 1.96(sd/√n)
...where ± 1.96 represents the 95% interval using a ztable, sd = standard deviation, and n = sample size
c). You are 95% confident that the population mean is within the interval.
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