A manager has computed the correlation between the number of hours of sick leave taken per year and the annual salary
14-49. A manager has computed the correlation between the number of hours of sick leave taken per year and the annual salary for the 200 employees in her company. The hours of sick leave range from 0 to 39, and the correlation coefficient for the two variables is r = − 0.19. Suppose the manager has another employee who was not included in the analysis and this employee took 71 hours of sick leave during the year. Discuss whether the correlation computed from the other 200 employees applies to this new employee.
Sample Answer
The correlation coefficient of r = -0.19 indicates a weak negative linear relationship between hours of sick leave taken and annual salary for the original 200 employees. This means that, in general, employees with slightly higher salaries tend to take slightly fewer hours of sick leave, and vice versa. However, the relationship is weak, suggesting that other factors likely have a much stronger influence on sick leave.
It is not appropriate to extrapolate this correlation to the new employee who took 71 hours of sick leave for several reasons:
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Extrapolation Beyond the Data Range: The original data only included employees with sick leave hours ranging from 0 to 39. The new employee’s 71 hours falls far outside this range. Correlations should not be extrapolated beyond the range of the original data. The relationship between sick leave and salary might be very different at extremely high levels of sick leave. It’s possible that the factors influencing sick leave at these extreme levels are different than those influencing sick leave within the 0-39 hour range.