Statistics
posted by Alex .
The heights of the students in a statistics class are approximately normal with mean 68 inches and a standard deviation of 2.75 inches. Suppose that the heights of the 15 male students in the statistics class are also approximately normal with mean 71 inches.
Would the standard deviation for the males in the class be greater than 2.75 inches, exactly 2.75 inches, or less than 2.75 inches?

I think there is a problem here. What if there are 215 students in the stat class, 15 of which are males. The remaining 200 are female. For the statistics class, the females overwhelm the males, so the Class statistics largely reflect the females, and the males is just down in the noise. Now standard deviation: I don't see how any analysis can be done without making some assumptions about class size.