A problem in a test given to small children asks them to match each of three pictures of animals to the word identifying that animal. If a child assigns the three words at random to the three pictures, find the probability distribution for Y , the number of correct matches.
Statistics 350 Fall 2006 Exam 1 Solutions (Answers with Explanations) 1. a. This is an experiment because the migraine patients were randomly divided into groups. b. Yes, the control group is the one in which the patients received no treatment. c. The number of headache days is the response variable since we are measuring the effectiveness of acupuncture and sham acupuncture by the extent to which they reduce the occurrence of migraine headaches. d. The variable “age” would be an example of a(n) confounding (or lurking) variable. The effects attributed to (sham) acupuncture may in fact be due to age in the situation described here. 2. None of these are appropriate because this is a bar