Chapter 36 Averages & Range

Types of Average  Range = largest- smallest  Mode = most common  Median = middle (when put in order)  Mean = total ÷ number

Example  The price of a can of cola in different shops is: 33, 34, 31, 32, 30, 31, 31, 35p Find(a) the range (b) the mode (c) the median (d) the mean

Discrete Frequency Distribution  Mode = value with highest frequency  Mean = Σfx ÷Σf Example The number of goals scored by a team are Number of Goals Number of Games

Grouped Frequency Distribution  Find the mid-point of the group for the x value Example The masses of a group of children are Example Mass (kg) Freq 40≤m<50 50≤m<60 60≤m<70 70≤m<

Ex 36.3 Q1 SalaryMid-pointFreq f × x 10≤s<15 15≤s<20 20≤s<25 25≤s<30 30≤s< Σf=127 Σfx= Mean = ÷127 = 15.1

Comparing Distributions  Compare these marks out of 10 between girls and boys Mark Number of boys Number of girls

Which is the Best Average? A youth group leader gets a discount if she buys all cans the same size. She took a vote on which size people wanted. Which size should she buy? Size (ml) Votes