Measures of Central Tendency- Mean

1. Copyright © 2012 Pearson Canada Inc., Toronto, Ontario
Slide 4- 1
Measures of Central Tendency
 Measures of central tendency provide information
about typical or average values of a data set.
 Mean, Median and Mode are the most commonly
used measures of central tendency.
 It is unique that a data set has one and only one
mean
 The value of the mean is influenced by all
observations in the data set

2. Copyright © 2012 Pearson Canada Inc., Toronto, Ontario
Slide 4- 2
Centre of a Distribution - Mean
 When a distribution is unimodal and symmetric,
most people will point to the centre of a
distribution.
 If we want to calculate a number, we can average
the data.
 We use the Greek letter sigma to mean “sum” and
write:
yTotal
y
n n
 

The formula says that to find the
mean, we add up the numbers
and divide by n.

3. Copyright © 2012 Pearson Canada Inc., Toronto, Ontario
Mean of a frequency distribution
 Mean =
𝑓𝑥
𝑓
Slide 4- 3

4. Copyright © 2012 Pearson Canada Inc., Toronto, Ontario
Slide 4- 4
Centre of a Distribution – Mean (cont)
 The mean feels like the centre because it is the point
where the histogram balances: