Page 69 - Mathematics Coursebook

6.3 Using frequency tables

6.3 Using frequency tables

Another way of collecting data is to use a data-collection sheet.

#is is a table in which you use tally marks to $ll in responses.
For example, you could use this data collection sheet if you were asking students in your class how
many brothers and sisters they had.

Number of 0 1 2 3 4 5 or more
brothers and
sisters

Every time you asked a student, you would put a tally mark in the table.
If the $rst ten students gave you answers of 0, 2, 1, 2, 1, 2, 2, 3, 5 and 2, your table would look like this.

Number of 0 1 2 3 4 5 or more
brothers and / // //// / /
sisters

Notice that the $"h tally mark is a diagonal line across the previous four. #is makes it easier at the end

to add up all the tally marks, as you can count them in groups of $ve – if you know your tables!
A frequency table is another type of data-collection sheet. It usually has three columns: the $ rst is for
the list of the items you are going to count, the second is for the tally marks and the third is for writing
the total number of tallies, which is the frequency.

Worked example 6.3

Here are the grades awarded to 30 students for their science project.

A C D C B B A B B C
D E A A C C C B C D
E D C C B B B B A C

a Put the results into a frequency table.
b How many students had Grade A?
c What was the most common grade?

a Grade Tally Frequency When you draw a frequency
A //// 5 table, always make sure the
B //// //// 9 tally column is quite wide
C //// //// 10 to make sure all the tallies
D //// 4 will fi t.
E // 2
Total: 30

b 5 students The frequency for Grade A is 5.
c Grade C The highest frequency is 10, so C is the most common grade.

68 6 Planning and collecting data