An investigator wishes to determine whether cannabis (or marijuana) consumption causes a change in the performance of drivers. Twentyvolunteers are matched for body weight and driving ability and then randomly assigned to either the experimental group or the control group. There were ten participants in each group. Both groups were asked to eat two chocolate chip cookies. The control group were given plain cookies but the experimental group was given cookies that contained cannabis. Performance was measured by the number of errors made on a driving simulator. Use the following summary statistics to answer the questions:

An investigator wishes to determine whether cannabis (or marijuana) consumption causes a change in the performance of drivers. Twenty volunteers are matched for body weight and driving ability and then randomly assigned to either the experimental group or the control group. There were ten participants in each group. Both groups were asked to eat two chocolate chip cookies. The control group were given plain cookies but the experimental group was given cookies that contained cannabis. Performance was measured by the number of errors made on a driving simulator. Use the following summary statistics to answer the questions: Experimental Group M1 = 28.70 [D = 59 Control Group M2 = 22.80 [D2 = 571 a) Which is the correct answer? (1 pt) This study is an example of a(n) 1. Matched pairs design 2. Successive repeated measures design 3. Simultaneous repeated measures design 4. Independent groups design b) In symbols or words, what is the null hypothesis for this experiment? (1 pt) c) In symbols or words, what is the alternative hypothesis for this experiment? (1 pt) d) Calculate the standard error of the difference scores (Note: you must find the standard deviation first). (3 pts) e) Calculate the t-test. (2 pts) f) What df do you need to determine the critical values? What are the t critical values? Assume a = .05. (1 pt) g) Do we reject or fail to reject the null hypothesis? (.5 pt) h) Is there a difference in the number of errors made as a function of cannabis consumption? Write up the results in APA format. (You don't need to include the standard deviations, because those were not given.) (1.5 pts)