lecture 17 and 18

Question 1

conditions for difference of means?

Answer 1

randomly selected in independent manner, approximately normal, variances are equal

Question 2

paired difference experiment

Answer 2

experiment in which observations are paired and the differences are analyzed; randomized block experiment

Question 3

blocking

Answer 3

comparisons within groups of similar experimental units

Question 4

conditions for large paired difference

Answer 4

target population, nd>30

Question 5

conditions for small paired difference

Answer 5

target population, approximately normal

Question 6

mean of proportion thing

Answer 6

p1-p2

Question 7

what is (phat1^2 - phat2^2)?

Answer 7

unbiased estimator for p1-p2

Question 8

standard deviation of standard deviation(phat1^2-phat2^2)

Answer 8

p1q1/n1 + p2q2/n2; approximately normal if n are large

Question 9

conditions for large samples

Answer 9

randomly selected, phat1-phat2 is normal, n1phat1>15, n1qhat1>15 and n2phat2>15, n2qhat2>15

Question 10

phat formula

Answer 10

x1+x2/n1+n2

Question 11

if you know standard error, the variance (or SD) of population, and the significance level of the test (a), then you can determine the sample size; give formulas

Answer 11

n1=(za/2)^2 (variance1 + variance2)/ (SE)^2