A researcher wants to know whether exposure to a political ad will change research subjects' likelihood of voting.In order to test her hypothesis, she asked her subjects to express their likelihood of voting on a 7 point scale ranging from 1(extremely unlikely to vote) to 7 (extremely likely to vote).She then shows them a political ad, and asks them the same question again.Based on the data below, can she be 95% confident that her subjects' attitudes about voting change from pre to post? (10 points)

Subject Pre Post

A 4 2

B 3 3

C 5 4

D 5 1

E 4 2

F 6 4

G 2 1

Pre Mean:________________

Post Mean:__________________

Standard deviation of differences:_________________

Standard Error:_________________

Calculated t-score:_______________

Can we ?reject the null hypothesis of no pre to post differences?__________________

I understand how to find the mean, but how do you find the deviation, error and t-score