Cambridge International Mathematics

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2 Copy and complete the following:

a If there is a positive association between the variablesxandy, then asxincreases,y.............

b If there is a negative correlation between the variablesTandd, then asTincreases,d..............

c If there is no association between two variables then the points on the scatter diagram are .............

...............

3a 10 students were asked for their exam marks in Physics and Mathematics. Their percentages are

given in the table below.

Student A B C D E F G H I J

Physics 75 83 45 90 70 78 88 50 55 95

Maths 68 70 50 65 60 72 75 40 45 80

i Draw a scatter diagram with the Physics marks on the horizontal axis.

ii Comment on the relationship between the Physics and Mathematics marks.

b The same students were asked for their Art exam results. These were:

Student A B C D E F G H I J

Art 75 70 80 85 82 70 60 75 78 65

Draw a scatter diagram to see is there is any relationship between the Physics marks and the Art

marks of each student.

4 The following table shows the sales of soft drinks in a shop each month, along with the average daily

temperature for the month.

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temp (oC) 7 10 11 13 15 19 22 25 23 18 11 8

Sales (thousands$) 12 8 10 15 16 18 22 25 20 15 16 12

Draw a scatter diagram with the independent variabletemperaturealong the horizontal axis. Comment

on the relationship between the sales and the temperature.

5 Students were asked to measure their height in centimetres and their shoe size. The results are recorded

in the table below:

Height (cm) 165 155 140 145 158 148 160 164 160 155 150 160

Shoe size 6 : 5 4 : 5 4 5 : 5 6 5 : 5 6 6 : 5 5 : 5 5 5 5 : 5

Comment on any relationship between height and shoe size.

y

xx

y y

x

458 Two variable analysis (Chapter 22)

IGCSE01

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Y:\HAESE\IGCSE01\IG01_22\458IGCSE01_22.CDR Monday, 27 October 2008 2:14:42 PM PETER