In Chapter 9, we examined a picture of winning time in men’s 500­meter speed skating plotted across time. The data represented in the plot started in 1924 and went through 2010. A regression equation relating winning time and year for 1924 to 2006 is winning time 5 273.06 2 (0.11865)( year)
a. Would the correlation between winning time and year be positive or negative? Explain.
b. In 2010, the actual winning time for the gold medal was 34.91 seconds. Use the regression equation to predict the winning time for 2010, and compare the prediction to what actually happened. Was the actual winning time higher or lower than the predicted time?
c. Explain what the slope of 20.11865 indi­cates in terms of how winning times change from year to year.