Question

1) State the null and alternative hypotheses (can be done in notation format, e.g. H₀:_, H₁:_ )

2) Compute (show all work, please):

            - Pooled estimate of the population variance

            - Variance of each distribution of means

            - Variance of the distribution of differences between means

            - Standard deviation of the distribution of differences between means

3) Set the criteria for a decision (i.e. state alpha, one- or two-tailed test, degrees of freedom and the cutoff score(s)

4) Compute the test statistic (t_obt)

5) Decide whether to retain/reject the null hypothesis & state your conclusion in APA format (Include: the type of t-test test used, what groups you are comparing and what you are measuring (e.g. the I.V. and D.V.), whether it was significant or not, your test statistic (e.g. t(df) = …,) and the means of time 1 and time 2; see the lecture slides for examples).

Problem 1:

A researcher wants to study the effectiveness of a new pain management therapy program for people with chronic pain. Because it is a new therapy, the researchers are unsure if the therapy will increase or decrease chronic pain. Thirty-two people who experience chronic pain agree to be in the study. The researcher randomly picks fourteen of these volunteers to be an experimental group that will go through the new pain management therapy. The other eighteen volunteers are put in a control group that will go through ordinary pain management techniques. A month after the study, each volunteer is asked to rate the effectiveness of their pain management on a 9-point scale from 1-9 (1 = minimal pain, 9 = maximum pain). The average score for individuals in the experimental group is (M₁) 3 (S²₁= 3.71), while the average score for individuals in the control group (M₂) 6 (S²₂= 4.8). (α = .05)

Answer 1

NULL HYPOTHESIS H0:

ALTERNATIVE HYPOTHESIS Ha:

Since P value= 0.00033

P value SMALLER THAN 0.05 THEREFORE SIGNIFICANT

DECISION: REJECT NULL HYPOTHESIS H0.

CONCLUSION: WE HAVE SUFFICIENT EVIDENCE TO CONCLUDE THAT THERE IS  effectiveness of a new pain management therapy program for people with chronic pain.