Apps. and Interpretation for IBDP Maths Ebook 1 | Page 321

4. The following table below shows the age x of a person and the score y on a memory
test of seven patients.
Age ( x ) 20 20 25 30 35 40 40
Score ( y ) 70 60 55 45 35 30 20
The above data is visualized by the scatter diagram below, where M(30, 45) represents
the mean point:
22
(a) Draw a suitable line of best fit on the scatter diagram.
[2]
(b) Using the line of best fit to estimate the memory test score of a patient when the
patient is 45 years old, giving the answer correct to the nearest integer.
[2]
This line of best fit would make unreliable estimates of the memory test score for patients
under the age of p or above the age of q , where p� q.
(c) Write down the values of p and q .
[2]
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