Analysis and Approaches for IBDP Maths Ebook 1 | Page 304

Your Practice Set – Analysis and Approaches for IBDP Mathematics
3. The maximum temperature t , in degrees Celsius, in a monument on four randomly
selected days is shown in the following table. The table also shows the number of visitors,
n , to the monument on each of those four days.
Maximum temperature ( t degrees Celsius) 2 5 7 1
Number of visitors ( n ) 50 48 63 15
The relationship between the variables can be modelled by the regression equation
n �at � b .
(a) (i) Find the value of a and of b .
(b)
(ii) Explain what a and b represent.
[4]
Use the regression equation to estimate the number of visitors on a day when the
maximum temperature is 4C � .
[2]
4. Six metal ingots were chosen at random and measurements were made of their breaking
strength s and their hardness h . The results are shown in the table below.
Breaking strength ( s tonnes per cm) 5 7 7.4 6.8 5.5 6.9
Hardness ( h ) 51 71 83 70 75 60
The relationship between the variables can be modelled by the regression equation
h �as � b.
(a) (i) Find the value of a and of b .
(b)
(ii)
Explain what a and b represent.
Use the regression equation to estimate the hardness of a metal ingot when its
breaking strength is six tonnes per cm.
[4]
[2]
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