Cambridge International Mathematics

696 ANSWERS

EXERCISE 13E

1a 1 b 2 c ¼ 1 : 90 d 3

2a i 5 : 74

ii 7

iii 8

iv 10

c bimodal

b

dThe mean takes into account the full range of numbers of

books read and is affected by extreme values. Also the values

which are lower than the median are well below it.

emedian

3a i 4 : 25 ii 5 iii 5 b 6 c Yes, negatively skewed.

dThe mean is less than the mode and median.

4aForeign countries visited Frequency

06

18

25

34

42

51

62

b 28 people

ci¼ 1 : 96

ii 1 : 5

iii 1

iv 6

EXERCISE 13F

1a 71 : 225

b 73 : 5

di 71 : 5

ii 74

every close

c Chem. exam mark fx fx

30 - 39 1 34: 534 : 5

40 - 49 2 44: 589 : 0

50 - 59 7 54:5 381: 5

60 - 69 6 64:5 387: 0

70 - 79 10 74:5 745: 0

80 - 89 10 84:5 845: 0

90 - 99 4 94:5 378: 0

40 2860

2a 8 : 41 b 6 - 10 lunches c ¼ 8

3a¼ 55 : 2 b¼ 58 : 3

c For this test the boys performed better than the girls.

EXERCISE 13G

1aHelen: mean¼ 18 : 8 , median=22

Jessica: mean¼ 18 : 1 , median=18

bHelen: range=38, IQR=15: 5

Jessica: range=29, IQR=6: 5

c Helen, but not by much.

dJessica: smaller range and IQR.

5aBoys: mean¼ 171 , median= 170: 5

range=28, IQR=7

Girls: mean¼ 166 , median= 166

range=25, IQR=7: 5

bThe distributions show that in general, the boys are taller

than the girls but there is little variation between their height

distribution.

REVIEW SET 13A

1adiscrete bcontinuous cdiscrete

2a 49 b 15 c 26 :5% dpositively skewed

e¼ 3 : 51 employees

3aNo. call-outs/day Tally Frequency

0 - 9 jj 2

10 - 19 ©jjjj©j 6

20 - 29 ©jjjj©©©jjjj 10

30 - 39 ©jjjj©jj 7

Total 25

b

c 17 days d8% e 20 - 29 call-outs/day

4ax¼ 29 : 6 b 16 and 28 c 29 d 45

e Q 1 =22,Q 3 =41: 5 f 19 : 5

5aTest scores Tally Frequency

0 - 9 j 1

10 - 19 jjj 3

20 - 29 ©©jjjj©©jjjjjj 12

30 - 39 ©©jjjj©©jjjjjjjj 14

Total 30

bc 4 students

d 46 :7%

6 x=7

7a 12 b 43 c 29 d 20 e 34 : 5 f 31 g 14 : 5

8aGoals/game Frequency

08

17

24

31

Total 20

bi 20 games

ii 18 goals

ci 0 : 9

ii 1

iii 0

iv 3

9 8 : 53 potatoes per plant

10 a x¼ 159 b 157 c 143 d 174

REVIEW SET 13B

1aThe number of children per household. bdiscrete

c Number of children Tally Frequency

00

1 ©jjjj© 5

2 ©jjjj©jj 7

3 jjjj 4

4 jj 2

5 j 1

60

70

8 j 1

Total 20

0

5

10

15

(^012345678910) no. of books read
frequency
mean
median
mode
Number of books read
0
5
10
0 10203040
frequency
no. of call-outs
Fire department call-outs
0
5
10
15
0 10203040test scores
frequency
Test scores
IB MYP_3 ANS
cyan magenta yellow black
(^05255075950525507595)
100 100
(^05255075950525507595)
100 100
Y:\HAESE\IGCSE01\IG01_an\696IB_IGC1_an.CDR Tuesday, 18 November 2008 4:18:21 PM PETER