No help from anyone the formula being used is _ _ 2 2
z= x1 -x2 divided by square root s1 + s2
-- ---
n1 n2
two samples of data determine if u can be 99% sure that company A makes more money than Company B
Co A Co B
mean 55,000 52,000
Std Dev 5,000 3,000
Sample size 200 400
I started out with z= 55,000-52,000
-----------------
V 5,000(2) + 3,000(2)
--------- ---------
200 400
Then, I get stuck?????? What do I do next to arrive at my answer?
Ok I got the formula mines just didn't type out like yours. My problem is actual help with numbers when I got to step three I have 3000 divided by 5830.95 then I got 1.94365. I don't know if I'm correct or what to do next.