The items are:
- In uncertain times, I usually expect the best
- It’s easy for me to relax
- I’m always optimistic about my future
- I enjoy my friends a lot
- My life doesn’t suck too much
- I don’t get upset too easily
- Overall, I expect more good things to happen to me than bad
The participants rated each question on a -3 (definitely not) to a +3 (definitely) scale. The researcher believes that their “optimism program” helps people become more optimistic. The null hypothesis is thus that no difference exists between the treatment and control groups.
For this assignment I want you to answer the following questions:
Are any of the seven optimism-scale questions “bad”? Tell me which one, and tell me how you know it’s bad. (Hint: there is 1 bad question).
Run a split-half correlation on the remaining 6 items. What is the correlation? Does this indicate that the scale is acceptable?
Run a t-test to see if there is a difference between the control group and the treatment group. What is the t-value, and should you “reject the null hypothesis”?