Choosing the Best Model Answers

The average daily print circulation for the Philadelphia Inquirer, a local newspaper, has declined each year since the year 2000. To develop a model for estimating circulation each year, the log of circulation (in thousands) was computed and plotted for a number of years since 2000.

The Bureau of Labor Statistics is an office within the US Department of Labor. Every three months the bureau releases a report containing jobs and salary data of US workers. One statistic reported is the median weekly salary for full-time workers. The scatterplot shows the growth of median weekly salary, starting in January 2010. An equation of the least-squares for the data in the scatterplot is , where 2010 represents year zero. The value of r for the scatterplot is 0.977.