1. State the assumptions governing the use of a t-test of a difference between the means of two independent groups.Which of the assumptions is most important and under what conditions would violations of this assumption be especially severe?

2. One study showed that swearing can help reduce ratings of pain. In the study each participant was asked to plunge a hand into icy water and keep it there as long as the pain would allow. In one condition the participants repeated their favorite curse words while their hands were in the water. In the other condition the participants repeated neutral words. In the study they also measured how long the participant could keep their hand in the water. The data are below.

Amount of time (seconds)

ParticipantsSwear wordsNeutral Words

19459

27061`

35247

48360

54635

611792

76953

83930

95156

107361

1)State the null hypothesis.

2)State the alternative hypothesis.

3)What is the critical t two tailed =.05?

4)Calculate the obtained T

S D = S D² =

SSd=

T=

5)What is the decision?

6)What type of error may you be making?

7)Calculate cohen's DUse SD for neutral words

8)Why is the correlated samples t-test more powerful than the sign test?