Page 391 - Math Smart - 7

Find the mode of the data set below.
14, 18, 16, 13, 16, 14, 15, 16, 14

Solutio
First, rearrange the data in ascending or descending order. In this example, the
data is arranged in ascending order:

13, 14, 14, 14, 15, 16, 16, 16, 18
Sometimes a set of data
Find the value that occurs most often.
does not have a mode.
In this data set, the values 14 and 16 each occur three times, which is also the This means that there is
highest frequency in the set. no value that occurs more
frequently than the other
We say this data set has two modes: 14 and 16. This data set is bimodal.
values.
.1a! class in grouped data

The manager of the Jurong Bird Park is planning the number of persons
needed to work in the ticket office during different times of the day.
She collected the data to find out when is the busiest period for the bird park.

Time interval No. of visitors
entering the park
This is the mode. 09 00-10 59 114 The most number
We say this is -► 11 00-12 59 340 < of people entering
the modal time 13 00-14 59 201 the park.
interval. 92
15 00-16 59
The most number of people entered the park between 11 00 to 12 59. The modal class of a set
This is the modal class of this set of grouped data. of grouped data is the
During which time period should the manager have the most staff working in class with the highest
frequency.
the ticket office?

A class of 40 pupils took their height measurements during their Physical
Education lesson. Their heights are recorded in the frequency table below. Find
the height interval that the majority of the pupils fall under.

Read this as Heiqht (cm) Number of dudIIs
"height more -► 130 ^ h < 134 1
than or equal to 135 £ h <139 0
130 cm but less 140 <h <144 2
than 134 cm". 145 <h <149 2
150^ h <154 7
154sh<159
Modal height . " 160 <h <164 7
interval 8 The greatest
165 <h <169 8 number of pupils in
170 ^h <174 10 4 this height interval.
175^ h<179 4
180 <h <184 0
185fih<189 1 387