Cambridge International Mathematics

Analysis of discrete data (Chapter 13) 281

Number of people Tally Frequency

10 to 19 jjjj©© 5

20 to 29 jjjj©©jjjj 9

30 to 39 jjjj©©jjjj©©j 11

40 to 49 jjjj 4

50 to 59 j 1

Total 30

EXERCISE 13B.2

23 7 1532134428152048

163432 5 221131102416

33 45 20 24 13 9 24 16 5 47

37 23 27 19 21 29 37 11 30 28

1 Forty students were asked to count the number of red cars

they saw on the way to school one morning. The results

are shown alongside.

a Construct a tally-frequency table for this data using class intervals 0 - 9 , 10 - 19 , ......, 40 - 49.

b Display the data on a vertical bar chart.

c How many students saw less than 20 red cars?

d

e

In this case we group the data into class intervals of length. The tally-frequency table is shown below.

We use the table to construct the vertical bar chart below.

The first column represents the values from to , the second from to , and so on.

10

10 19 20 29

0

2

4

6

8

10

12

0 102030405060

frequency

number of people

Lunch-time customers

What is the modal class for the data?

38 27 29 33 18 22 42 27 36 30 16 23 34

22 19 37 28 44 37 25 33 40 22 16 39 25

2

a Construct a tally and frequency table for this data.

b Draw a vertical bar chart to display the data.

c

d On how many days were at least 30 chairs made?

e Find the modal class for the data.

515 432 674 237 445 510 585 411 605 332 196

432 527 421 318 570 640 298 554 611 458 322

584 232 674 519 174 377 543 630 490 501

139 549 322 612 222 625 582 381 459 609

3 Over a 6 week period, a museum keeps

a record of the number of visitors it

receives each day. The results are:

a Construct a tally and frequency table for this data using class intervals 0 - 99 , 100 - 199 ,

200 - 299 , ......., 600 - 699.

b Draw a vertical bar chart to display the data.

c On how many days did the museum receive at least 500 visitors?

d What is the modal class for the data?

e Describe the distribution of the data.

What percentage of students saw at least 30 red cars?

The data gives the number of chairs made

each day by a furniture production company

over 26 days:

On what percentage of days were less than 40 chairs made?

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y:\HAESE\IGCSE01\IG01_13\281IGCSE01_13.CDR Thursday, 16 October 2008 9:31:32 AM PETER