
Question 14


The number of cars that called at a petrol station on some days of a month is as shown in the table.
Days of the month (x) 
3 
5 
8 
12 
15 
19 
22 
26 
Number of cars (y) 
143 
95 
112 
110 
104 
86 
78 
69 
(a) Represent this information on a scatter diagram.
 Draw the line of best fit to pass through the point (, ) where is the mean of x and is the mean of y.
 Use your diagram to estimate
 the day 80 cars called at the station;
 how many cars a petrol attendant at the station should expect on the 25th day.

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The report stated that majority of the candidates attempted this question and they performed very well in it. They were able to obtain as 13.75 and as 99.625. Majority of them were also able to draw the line of best fit to pass through the point (13.75, 99.625). The day 80 cars called at the station was day 18 while 74 cars should be expected on the 25th day. 


