An experiment was conducted to study the effect on sleeping time of increasing the dosage of a certain barbiturate. Three readings were made at each of three dose levels:

Sleeping Time (Hrs) Dosage (M/kg)

Y X 4 3 6 3 5 3 9 10 8 10 7 10 13 15 11 15 9 15

Y = 72 X = 84

Y2 = 642 X2 = 1002

XY = 780

a. Plot the scatter diagram.

b. Determine the regression line relating dosage (X) to sleeping time (Y).

c. Place a 95% confidence interval on the slope parameter .

d. Test at the 0.05 level the hypothesis of no linear relationship between the two variables.

e. What is the predicted sleeping time for a dose of 12 M/kg?