A psychology student hypothesized that lesions in a certain area of the brain, called the thalamus, decrease pain perception. He attempted to test this hypothesis, and conducted an experiment in which he randomly separated 16 rats into two groups of 8 participants. The rats in the experimental group, or first group, received a small lesion in the thalamus, part of the brain that the student thought was involved in pain perception. Rats in the control group, or second group, received a lesion in a part of the brain that was not involved with pain. Three weeks after surgery, each rat received a brief electric shock to the paws. This shock was administered in ascending order: it was started at a very low intensity level and increased until the animal drew back its paw. In this way, the pain threshold elicited by the electric shock was determined for each rat. The following data were obtained. The higher the current level, expressed in milliamperes, the higher the pain threshold.

The following data were collected: experimental group: .09, .08, .02, .07, .06, .08, .09, .09, 1.2; control group: 1.2, 1.8, 1.9, 1.3, .09, .08, 1.7, 1.6. The student chose as a probability criterion of .05. Answer:

1. What is the problem?_________________________ 2. What is the dependent variable?________________ 3. What is the independent variable?_______________ 4. What is the empirical hypothesis?___________________ 5. What is the null hypothesis?_________________ 6. 6. What is the alternative hypothesis?___________________ 7. What is the experimental hypothesis?______________

8. 1) n1=____ 2) n2=_____ 3) X1=____ 4) X2=_____ 5) X1 Average=______ 6) X2 Average=______ 7) X21=____ 8) X22=_____ 9) SS1 =_____ 10) SS2 = _____ 11) df = ______ 12) tc= ______

9. P_____(=,<,>) .05 10. Was the null hypothesis rejected?___ Why?-______ 11. Was the empirical hypothesis confirmed?__ Why?____ 12. Was the alternative hypothesis accepted? Why?______ 13. Which of the two conditions or values of the independent variable which of the two conditions or values of the independent variable produced the change in the dependent variable? dependent variable? _________ 14. Type of tail used: A) One tail. B) Two tails 15. Type of research: A) Deductive hypothetical B) Inductive