19

Question 1

To approximately achieve a desired margin of error E with approximate CI, the sample size should be at least?

Answer 1

0.25(Z_alpha/2 / E)^2

Question 2

Big assumption for the number of successes in successes and failures of confidence intervals?

Answer 2

Must be at least 10.

Question 3

Margin of error equation (E)?

Answer 3

Z_alpha/2 SE(P^)

Question 4

Z_alpha/2 is essentially a?

Answer 4

Quantile of 1 - alpha.

Question 5

When assumptions are not met,
P^?

Answer 5

(P^ - p)/SE(P^) have an unknown distributions.

Question 6

What happens when computing the margin of error when you don’t meet the assumptions?

Answer 6

You don’t know how much of the distribution should you cut off since you won’t know what quantile to use.

Question 7

If you have two independent normal distributed random variables, X and Y, the sum of R = X +- Y is also?

Answer 7

normally distributed

Question 8

Conditions for the confidence interval for the difference of means? 3•

Answer 8

•two populations (1,2) have been predetermined
•each pop distribution is normally distributed or not extremely skewed with unknown means and variances.
•independent random samples of size n1 and n2 have been collected from each population where min(n1,n2) is large enough to ensure the central limit theorem has sufficiently taken effect.

Question 9

Assumptions when estimating SE(x bar_1 - x bar_2)?

Answer 9

•Know that Sigma_1 = sigma_2. Since that means more data, we can make a better guess, so s_p ^2 is a pooled estimate for common sigma^2.

•Unsure if sigma_1 = sigma_2.

Question 10

Confidence intervals comparing two populations if the independent random variables are normally distributed?

Answer 10

R = X +- Y. X +- Y ~ Normal(mu_x +- my_y, sigma_x^2 + sigma_y^2)