Question: As study was made of the stopping distance of a 1300 kilogram car under perfect weather conditions at various driving speeds. The results, for a sample of n=6 trials, are shown in the following table:

Speed of the car Stopping Distance

(In kilometered per hour) (in meters)

(x) (y)

30 11

50 19

60 34

80 52

100 85

110 95

To save calculation time, you may use the following sums and sums of squares and cross products for subsequent calculations:

Ex=430 Ey=296 SSxx=4683.3333 SSyy=5989.3333 SSxy=5216.6667

a) Construct a scatter diagram for these data

b) Calculate the least squares regression line with stopping distance (y) as the dependant variable and speed of car (x) as the independent variable.

c) Plot the regression line on your scatter diagram. Show your calculation for x=40 and x=100

d) Interpret the value of "b" in the sample regression line

e) Construct a 99% confidence interval for B (Assume sb=0.0976)

f) Construct a 95% prediction interval for the stopping distance of the car when its speed is 70 kph. (Assume se=6.68)

g) What percent of stopping distance is explained by its linear relationship with the speed of the car