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Further Mathematics Paper 2, May/June. 2009  
Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Main
General Comments
Weakness/Remedies
Strength



Question 15

TThe table below shows the corresponding values of two variables x and y.


x

33

31

28

25

23

22

19

17

16

14

y

  4

  6

  4

10

12

10

14

15

18

22

(a)Plot a scatter diagram to represent the data.
(b) Calculate the mean of x‾ and y‾ , the mean of y‾
(c)(Drawthe line of best fit to passthrough(x‾, y‾)                                                                                 
(d)   From your graph in (c), determine the
                    (i)      relationship between X and Y.

                    (ii)      value of Y when X is 24.            
_____________________________________________________________________________________________________
Observation

It was reported that majority of the candidates who attempted this question performed very well especially in parts (a) and (b).  They were able to represent the data on a scatter diagram, compute the means (x‾) of x and (y‾) of y correctly, as (x‾) =228/10  = 22.8 and (y‾) =115/10  = 11.5. Fewer candidates were able to draw the line of best fit passing through the point (x‾,y‾). They were able to obtain the relationship between x and y using the expression y = mx + c where m is the slope of the line and is equal to -0.67, c = intercept on the y –axis = 27.  i.e. y = -0.67x + 27.  The value of y when x = 24, which should be obtained from the graph, was 10.5.

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