Student researchers tested to see whether listening to music while memorizing words would interfere with a person’s ability to memorize words. Their subjects were randomly assigned to either listen to music or not. Everyone was shown 40 five-letter words for 90 seconds. The words were taken away and they were asked to write down as many words as they could remember. The results are in the file WordsMemorized. 

a. Is this an experiment or an observational study? 

b. What is the explanatory variable? Is it categorical or quantitative? 

c. What is the response variable? Is it categorical or quantitative? 

d. Use the Descriptive Statistics applet to make dotplots and boxplots of the data. Give a brief comparison of the two distributions by including measures of center, variability, shape and any unusual observations. 

e. Which group, music or not, tended to remember more words? How are you deciding? Does this provide preliminary evidence in favor of the students’ research conjecture?