What is the value of the sample mean?
Z = (mean1 - mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√n
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score.
Scores on an SAT test have a mean of μ = 1026 and a standard deviation of σ = 209. Compute the margin of error of the sample mean for a random sample of 100 students.
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