Answer in Statistics and Probability for smilynne #250376
October 24th, 2022
1. Explain the difference between testing a single mean and testing the difference between two means.
2. What two assumptions must be met when you are using the z test to test differences between two means? Can the sample standard deviations 1 and 2 be used in place of the population standard deviations 1 and 2?
1.
for z- test:
testing a single mean:
“H_0:mu=A”
“H_a:muneq A”
“z=frac{x-mu}{sigma}”
testing the difference between two means:
“H_0:mu_1=mu_2”
“H_a:mu_1neq mu_2”
“z=frac{mu_1-mu_2}{sqrt{sigma_1^2/n_1+sigma^2_2/n_2}}”
2.
It can be:
“sigma_1=sigma_2” or “sigma_1neqsigma_2”
The sample standard deviations 1 and 2 cannot be used in place of the population standard deviations 1 and 2.
“s_1=sigma_1/sqrt{n_1}, s_2=sigma_2/sqrt{n_2}”
