The article \"Characterization of Highway Runoff in Austin, Texas, Area\" (Jr Environ. Engr. 1998: 131137) gave a scatterplot, along with the least squares line, of x = rainfall volume (m3) and y = runoff volume (m3) for a particular location. The accompanying values were read from the plot. x 5 12 14 17 23 30 40 4? y 4 10 13 15 15 25 27 46 :1: 55 67 72 81 96 112 127 y 38 46 53 70 82 99 100 (a) Does a scatterplot of the data support the use of the simple linear regression model? (b) Calculate point estimates of the slope and intercept of the population regression line. (c) Calculate a point estimate of the true average runoff volume when rainfall volume is 50. (d) Calculate a point estimate of the standard deviation 0'. (e) What proportion of the observed variation in runo volume can be attributed to the simple linear regression relationship between runoff and rainfall