# Thread: Hypothesis Testing need steps

1. ## Hypothesis Testing need steps

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?

2. ## Re: Hypothesis Testing need steps

No help from anyone the formula being used is _ _ 2 2
z= x1 -x2 divided by square root s1 + s2
-- ---
n1 n2

3. ## Re: Hypothesis Testing need steps

$\displaystyle t_{calc}= \frac{ \bar{x_1}- \bar{x_2} }{ \sqrt{ \frac{s_1^2}{n_1}+\frac{s_2^2}{n_2} } }$

$\displaystyle df = \frac{ \left( \frac{s_1^2}{n_1}+\frac{s_2^2}{n_2}\right)^2 }{ \left( \frac{\left( \frac{s_1^2}{n_1}\right)^2}{n_1-1}+\frac{\left( \frac{s_2^2}{n_2}\right)^2}{n_2-1} \right) }$

reject $H_0$ if $|t_{calc}|> |t_{df, 1-\alpha}|$

4. ## Re: Hypothesis Testing need steps

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.