AnSWErS to tHE StudEnt'S Book ExErCiSES - Hodder Plus Home

2 a) You are aged 19 up until your 20th birthday,which is 20 years after you were born.b)Age(years)Under1010–19 20–29 30–49 50–89Frequency 24 46 81 252 288Frequencydensity2.4 4.6 8.1 12.6 7.2Frequency density(people per year)151050 20 40 60 80 100Age (years)3 a) Waiting time(w minutes)Frequency0 , w < 20 5020 , w < 40 8240 , w < 60 13060 , w < 90 15390 , w < 120 42120 , w < 180 24b) 60.2 minutes to 1 d.p.4 a) 5 girls and 18 boysb) Possible answers:In general, boys spent less time on thephone.The times for the girls were more evenlyspread than those for the boys.There were 50 girls and 50 boys represented.5 a) 100b) 81.2 kg to 1 d.p.Mixed exercise 44 (page 596)1 a) Height (h cm) Cumulativefrequencyh < 120 0h < 130 5h < 140 32h < 150 71h < 160 133h < 170 178h < 180 196h < 190 200b)Cumulative frequency200180160140120100806040200120 130 140 150 160 170 180 190Height (h cm)c) Median 5 155 cm, IQR 5 19 cm2 a) 12b) 35c) Approximately 9.5 km3 Age (years) Under 10 10–19 20–29 30–49 50–89Frequency 240 1460 2080 4950 6120Frequencydensity(people peryear)24 146 208 247.5 153Frequency density2502001501005000 10 20 30 40 50 60 70 80 90Age (years)4 Distance (km) Frequency0 , x < 10 610 , x < 15 715 , x < 20 920 , x < 25 1225 , x < 30 530 , x < 40 7Mean 5 20.2 km (to 1 d.p.)5 Suitable comments include the following.The second group did not run as far as the first,on average.The distances for the second group were not asspread out as those for the first (comparativelymore ran between 10 and 25 km).The estimate of the range is the same for bothgroups (both distributions go from 0 to 40 km).6 a) 21.1b) 75 and 85c) 16Higher WJEC GCSE Mathematics © 2010, Hodder EducationAnswers to the Student’s Book exercises 243