I'm not sure what they are getting at.
Wild guess?
Difference OF |x-y|?
Difference BETWEEN (x-y)?
Independent random samples from 2 normally distributed populations give the following results
n_x= 10 x=480 s_x=30
n_y= 12 y= 520 s_y= 25
A) If we assume that the unknow population variances are equal , what is the 90% confidence interval for the difference OF population means?
B) If we assume that the unknow population variances are equal , what is the 90% confidence interval for the difference BETWEEN population means?
OF vs. BETWEEN? Where is the difference? What is he asking? I just know a formula that is (x-y) + or - t* sqroot [(s2_p/n_x) + (s2_p/n_y) ]
Help. Please.