• Median: the middle value in an ordered list of data • If an odd number of sample then chose the median as the middle • If even number then the median is average of the 2 middle sample • Mode: value in the dataset that occur most frequently • Mean: Average value of the data • Measure of dispersion: how much data is spread or dispersed • Range of the data: Difference between largest and smallest values

1. Understanding Statistics
Median, Mean and Range of Data

2. Median and Mode
 Median: the middle value in an ordered list of data
 If odd number of sample then chose the median as the middle
 If even number then median is average of the 2 middle sample
 Mode: value in dataset that occur most frequently
 Situation: House price sold in suburb xyz last month in MM
Mean is 12.15/8 = $1.518 MM
Median is (1.25+1.3)/2 = $1.275 MM
Mode is $1.2 MM
 Interpretation: the mean > median because of $3.1 MM house and the median can misrepresent the
house prices for that suburb. If I sell based on the mean I might be disappointed. It might mislead
you
 If I want to invest, “mode” tells me which houses are the most successful in term of being
transitioned
$1.20
$1.40
$1.20
$1.30
$1.50
$1.20
$1.25
$3.10

3. Range of Data
 Measure of dispersion: how much data is spread or dispersed
 Let’s consider age of people in a room at a party:
 Party 1: 15 16 16 17 17 17 18 19
 Party 2: 4 7 12 17 20 22 24 28
 Both parties the mean is around 17 but party 2 is speeded on a wider range
 Range of the data: Difference between largest and smallest values
 P1 Range = 19 -15 = 4
 P2 Range = 28 – 4 = 24
 Disadvantage: if data have outliers will skew the result
 Let’s suppose at P2 the grandpa will show up and he is 98 yo!
 In this situation you might want to rerun the calculation without the outliers