358 Continuous data (Chapter 17)
a Histogram showing cross-country times b The modal class is 266 t< 31.
c Middle value (x) Frequency (f)
21 : 5 27
24 : 5 51
28 : 5 100
36 75
The mean¼ 29 : 2 mins.
EXERCISE 17B
1 Students were asked to draw a sketch of their favourite fruit. The time taken (tmin) was measured for
each student, and the results summarised in the table below.
Time (tmin) 06 t< 2 26 t< 4 46 t< 8 86 t< 12
Frequency 10 15 30 60
a Construct a histogram to illustrate the data.
b State the modal class.
c Use a graphics calculator to estimate the mean time.
2
a Represent this data on a histogram.
b Find the modal class.
c
3
Distance (dm) 206 d< 25 256 d< 35 356 d< 45 456 d< 55 556 d< 85
Frequency 15 30 35 25 15
a Draw a histogram of the data.
b What is the modal class?
c
4
10 20 30 40 50 60
time ( min)t
frequency density
Travel times to work
0
Use a graphics calculator to estimate
the mean distance thrown.
The histogram shows the times spent travelling to
work by a sample of employees of a large corporation.
Given that people took between and minutes
to get to work, find the sample size used.
60 10 20
Use technology to estimate the mean mass.
A group of students was asked to throw a baseball as far as they could in a given direction. The results
were recorded and tabled. They were:
Mass (mkg) 406 m< 50 506 m< 60 606 m< 65 656 m< 70 706 m< 80
Frequency 25 75 60 70 30
When the masses of people in a Singapore fitness club were measured, the results were:
0
5
10
15
20
20 22 24 26 28 30 32 34 36 38 40
time ( min)t
frequency density
key represents
10 students
IGCSE01
cyan magenta yellow black
(^05255075950525507595)
100 100
(^05255075950525507595)
100 100
Y:\HAESE\IGCSE01\IG01_17\358IGCSE01_17.CDR Tuesday, 18 November 2008 11:49:41 AM PETER