A study was undertaken to examine the data for 44 physicians working for an emergency department at a major hospital so as to determine- which of a number of factors are related to the number of complaints received during the preceding year. In addition to the number of com-plaints, data available consist of the number of visits-which serves as the size for the observation unit, the physician-and four other factors under investigation. Table E2.34 presents the complete data set. For each of the 44 physicians there are two continuous explanatory factors, revenue (dollars per hour) and workload at the emergency service (hours), and two binary variables, gender (female/male) and residency training in emergency services (no/yes). Divide the number of complaints by the number of visits and use this ratio (number of complaints per visit) as the primary outcome or endpoint X.

(a) For each of the two binary factors, gender (female/male) and resi- dency training in emergency services (no/yes), which divide the 44 physicians into two subgroups-say, men and women-calculate the mean x and standard deviation s for the endpoint X.

(b) Investigate the relationship between the outcome, number of com-plaints per visit, and each of two continuous explanatory factors, revenue (dollars per hour) and workload at the emergency service (hours), by calculating Pearson's correlation coefficient, and draw your conclusion.

(c) Draw a scatter diagram to show the association, if any, between the number of complaints per visit and the workload at the emergency service. Does it appear to be linear?

TABLE E2.34

Note: This is a very long data file; its electronic copy, in a Web-based form, is avail- able from the author upon request.