Statistics
posted by Mike .
An organization is studying whether women have caught up to men in starting pay after attending college. They randomly sampled 28 women, who earned an average of $38,293.78 out of college with a standard deviation of $5,170.22. Twentyfour men were also randomly sampled, and their earnings averaged $41,981.82 with a standard deviation of $3,195.42. Using a significance level of 0.02, do these data provide strong evidence that women have not yet caught up to men in terms of pay? If so, can we make a causal con clusion? If so, explain why. If not, provide an example of why the causal interpretation would not be valid.

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 related to the Z score. 
The probability of being a smoker for a population of college students is 0.20.The standard deviation for samples of 1600 students is 0.01. The standard deviation would be smallest for which of these sample sizes?
A) 16