The sampling distribution of the difference between 2 sample means

Question 1

What sample t-test do we use when we have measured anxiety in a group who had had counselling (POST) and a different group of people who would have counselling the following day (PRE)?

Simply = Between subjects design

Answer 1

Independent groups t-test

Question 2

What sample t-test do we use when we have measured the hunger levels of a group of people post-eating a hamburger and the same group of people’s hunger levels post-eating a salad?

Simply = Within subjects design

Answer 2

Paired/related sample t-test

Question 3

Which sample t-test involves repeatedly sampling scores from pop A and scores from pop B, then taking the means of these samples and taking the difference between the sample means?

Answer 3

Independent groups t-test

Question 4

To generate a distribution of differences between sample means, we must…?

Answer 4

Repeatedly sample scores from pop. A and scores from pop B, then taking the means of these samples and taking the difference between the sample mean

Question 5

What is the formula to find the difference between the 2 means in the 2 different conditions?

Answer 5

D = mean A - mean B

Question 6

What is the formula used to find the s.d. difference between the 2 populations in the 2 different conditions?

Answer 6

SQRT (s.e. (A) ^2 + s.e. (B) ^2)
or
SQRT (var A / N) + (var B / N)

Question 7

What is the formula for the independent groups z score?

Answer 7

z = (sample mean A - sample mean B) - (pop. mean A - pop mean B OR 0) / SQRT (s.e. (A) ^2 + s.e. (B) ^2)

Question 8

What is the formula for the independent groups t score?

Answer 8

t = (s. mean A - s. mean B) - (pop. mean A - pop mean B OR 0) / SQRT (e.s.e. (A) ^2 + e.s.e. (B) ^2)

Question 9

Usually when we test the null hypothesis, the pop. mean difference is…

Answer 9

Zero (0)

Question 10

What is v when we follow the independent groups sample t-test?

Answer 10

v = (Na + Nb) - 2