statistics
posted by Byron .
sample a recent study reports that older adults who got regular physical exercise experienced fewer symptoms of depression, even when tested 2 years late.
regular excersize scores= 1,3,4,3,5,2,3,4
no regular excersize scores=5,4,6,3,5,7,6,6
a)calculate the mean and the standard deviation for each group of score.
b)based on the statistics part, does there appear to be a difference between two groups?

my numbers look off. please help? thank you.

Group 1
mean = (1/8)* sum of your numbers, Call each Xi so (1/8)sum of Xi from i = 1 to 8
sigma^2 = (1/7)[ sum of (Ximean)^2] from i = 1 to 8
find sigma^2 and take the square root to find sigma
Do the same for group 2
See if the two means + or  their sigmas overlap significantly. If so, then you probably can not say much about how important exercise is to depression.