The mean SAT score for 13 male high school students is 500 and the standard deviation is 100. The mean SAT score for 16 female high school students is 490 and the standard deviation is 80. At o=.05 sigma sign are male SAT scores more varied than female? (Sigma=.05)

Answer 1

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 of the Z score in relation to .05.