Cambridge International Mathematics

ANSWERS 695

EXERCISE 13B.2

1aNumber of red cars Tally Frequency

0 - 9 jjjj 4

10 - 19 ©©jjjj©©jjjjj 11

20 - 29 ©©jjjj©©jjjjjjj 13

30 - 39 ©jjjj©jjj 8

40 - 49 jjjj 4

Total 40

b

c 15 students d30% e 20 - 29 red cars

2aChairs made per day Tally Frequency

10 - 19 jjjj 4

20 - 29 ©jjjj©©jjjj© 10

30 - 39 ©jjjj©jjjj 9

40 - 49 jjj 3

Total 26

b

c 88 :5% d 12 days e 20 - 29 chairs/day

3aVisitors each day Tally Frequency

0 - 99 0

100 - 199 jjj 3

200 - 299 jjjj 4

300 - 399 ©jjjj©j 6

400 - 499 ©jjjj©jjj 8

500 - 599 ©©jjjj©jjjj©jj 12

600 - 699 ©jjjj©jjjj 9

Total 42

b

c 21 days d 500 - 599 visitors enegatively skewed

4aYear 12 students Tally Frequency

50 - 59 jj 2

60 - 69 ©©jjjjjj 7

70 - 79 ©©jjjj©©jjjj 10

80 - 89 ©©jjjjjjj 8

90 - 99 jjj 3

Total 30

b

c 11 schools d 30% e 70 - 79 students

fa symmetrical distribution

EXERCISE 13C

1a i 24 ii 24 iiino mode

bi 13 : 3 ii 11 : 5 iii 8

ci 10 : 3 ii 10 : 0 iii 11 : 2

di 428 : 6 ii 428 iii 415 and 427

2aA: 7 : 73 , B: 8 : 45 bA: 7 , B: 7

cThe data sets are the same except for the last value, and the

last value of A is less than the last value of B, so the mean

of A is less than the mean of B.

dThe middle value of the data sets is the same, so the median

is the same.

3amean:$582 000, median:$420 000, mode:$290 000

bThe mode is the second lowest value, so does not take the

higher values into account.

cNo, since the data is unevenly distributed, the median is not

in the centre.

4amean: 3 : 11 , median: 0 , mode: 0

bThe data is very positively skewed so the median is not in

the centre.

cThe mode is the lowest value so does not take the higher

values into account.

5a 44 b 44 c 40 : 6 dincrease mean to 40 : 75

6105 : 6 71712 km 8 $2 592 000 9 x=12

10 a=8 11 27 127 : 875

13 A=^30 S+31O+30N

91

1415

EXERCISE 13D

1a i 9 ii Q 1 =7,Q 3 =10 iii 7 iv 3

bi 18 : 5 ii Q 1 =16,Q 3 =20 iii 14 iv 4

ci 26 : 9 iiQ 1 =25: 5 ,Q 3 =28: 1 iii 7 : 7 iv 2 : 6

2amedian=2: 35 ,Q 1 =1: 4 ,Q 3 =3: 7

brange=5: 1 , IQR=2: 3

ci...... greater than 2 : 35 minutes

ii ...... less than 3 : 7 minutes

iii The minimum waiting time was 0 : 1 minutes and the

maximum waiting time was 5 : 2 minutes. The waiting

times were spread over 5 : 1 minutes.

3a 20 b 58 c 40 d 30 e 49 f 38 g 19

Red car data

0

5

10

15

0 1020304050

no. of red cars

frequency

0

5

10

15

0 100 200 300 400 500 600 700

visitors/day

frequency

Museum visitors

0

5

10

0 1020304050

chairs

made

per day

frequency

Production of chairs

0

5

10

50 60 70 80 90 100

no. of Year 12 students

frequency

Year 12 student enrolments

IB MYP_3 ANS

cyan magenta yellow black

(^05255075950525507595)
100 100
(^05255075950525507595)
100 100
Y:\HAESE\IGCSE01\IG01_an\695IB_IGC1_an.CDR Thursday, 20 November 2008 4:11:08 PM PETER