Analysis and Approaches for IBDP Maths Ebook 1 | Page 306

Your Practice Set – Analysis and Approaches for IBDP Mathematics
Exercise 99
1. The following table below shows the distributions of the values of x and y .
x 900 960 975 1020 1045 1070
y 650 647 673 643 612 608
Let L
1
be the regression line of x on y . The equation of the line L
1
can be written in the
form x �ay � b .
(a) Find the values of a and b .
Let L
2
be the regression line of y on x . The lines L
1
and L
2
pass through the same
point with coordinates ( e, f ) .
(b) Find the values of e and f .
[2]
[3]
2. The following table below shows the distance d in kilometres and the cost c in pounds
of each of five taxi journeys.
Distance ( d km) 9 7.5 5 3.5 8
Cost ( c pounds) 9.2 7.9 6.1 4.7 8.5
Let L
1
be the regression line of d on c . The equation of the line L
1
can be written in the
form d �ac � b .
(a) Find the values of a and b .
Let L
2
be the regression line of c on d . The lines L
1
and L
2
pass through the same
point with coordinates ( mn. , )
(b) Find the values of m and n .
[2]
[3]
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