means from frequency tables a learning object produced by sidney tyrrell, coventry university, as...
TRANSCRIPT
Means from Frequency Tables
A Learning Object produced by
Sidney Tyrrell, Coventry University,
as part of her National Teaching Fellowship project.
To find the mean number of letters you receive per day
• You might keep a record for 10 days of the number of letters you receive each day,
• and summarise the results in a table.
like this
Number of letters per day frequency
5
2
3
3
4
2
To find the mean it is important
• to remember you want the average number of letters per day.
• So need the total number of letters,
• and total number of days.
The total number of letters is given by
Number of letters per day
frequency Letters x frequency
2 5
3 2
4 3
2 x 5 = 103 x 2 = 6
4 x 3 = 12
Total letters = 28
and the total number of days is
Number of letters per day
frequency Letters x frequency
2 5
3 2
4 3
2 x 5 = 103 x 2 = 6
4 x 3 = 12
Total letters = 28days = 10
days = 10 letters = 28
• The mean is
Total letters
Total days=
28
10= 2•8
The mean is 2•8 letters per day