Kylah
05-08-2006, 10:06 AM
I'm tearing my hair out over this Stats problem:
Age at onset of dementia was determined for a sample of adults between the ages of 60 and 75. For 15 subjects, the results were ∑X=1008 and ∑X²=67878. What is the mean and s for this data?
I've calculated the mean at 67.2, but how would I calculate the standard deviation? The formula that I have is s=√∑(X-mean)²/N-1, but that doesn't seem to fit here. I'm really frustrated, as the professor didn't go over this in class and the book doesn't cover it, yet I'm expected to do it. :shakehead
I'm in a distance learning course, so it's difficult to ask the professor for help.
Age at onset of dementia was determined for a sample of adults between the ages of 60 and 75. For 15 subjects, the results were ∑X=1008 and ∑X²=67878. What is the mean and s for this data?
I've calculated the mean at 67.2, but how would I calculate the standard deviation? The formula that I have is s=√∑(X-mean)²/N-1, but that doesn't seem to fit here. I'm really frustrated, as the professor didn't go over this in class and the book doesn't cover it, yet I'm expected to do it. :shakehead
I'm in a distance learning course, so it's difficult to ask the professor for help.