A college offers Information Technology courses. The course of managing

the courses depends on the number of registered students. The table below

shows a record of number of registered students and the management cost:

Number of

students 18 36 45 22 69 72 13 33 59 79 10 53

Cost

( RM1000) 37 54 63 42 84 91 33 49 79 98 32 71

(a) Find the least squares regression line of cost on number of students.

(b)Plot the data on a scatter diagram and draw the regression line.

(c) Interpret the values of "a" and "b" in the regression line obtained in (b).

(d) From the regression line, estimate the management cost if there are 90

registered students. Comment on the reliability of your estimate.