The data to the right represent the time (in seconds) to complete a 400-meter race while a wind is blowing 2 meters per second in different directions. The wind direction is measured from the finishing straight (so 180 degrees is a head on wind). See the figure. The wind speed of 2 meters per second is the strongest wind speed allowed for a world record to be recorded withoutthe notation "wind assisted."

(a) Draw a scatter diagram of the data. What type of relation appears to exist between x and y?
(b) Find the quadratic regression equation yn = b0 + b1x + b2x2.
(c) Draw a residual plot against the fitted values, x, and x2. Also, draw a boxplot of the residuals. Are there any problems with the model?