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Averages…. In table form. We will start with discrete data. i.e. the data can only take certain values e.g. shoe size. Number of children in a car. The mode means ……. most common. The mode is ……. 1 child per car. The range is the. Highest number of children – smallest number (per car).
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Averages….. In table form
We will start with discrete data i.e. the data can only take certain values e.g. shoe size
The mode means ……. most common
The mode is ……. 1 child per car
The range is the Highest number of children – smallest number (per car)
So the range = 4 – 0 = 4
It is NOT ….. 9 – 1 = 8
Put in size order (Already done in our table) Find the middle value median
We have 20 pieces of data To find the position of the data value we need…. • Add 1 onto the number of data values 21 • Half this 10½ • We need to look halfway between the 10th and 11th pieces of data 1 and 1 • So the median is ……….
Now for the trickiest bit…. The mean
We need to find the total number of children in the cars And then divide by the total number of cars
Mean number of children per car …… Total No. of children ÷ total frequency
Mean = 29 ÷ 20 = …….. 1.45 children per car
Mode (most common) = … 0 rings
Range = ……. 4 rings – 0 rings = 4
Median …… • 100 pieces of data • Do the ‘add one and half business’ which leaves us looking for the 50½ value (in between the 50th and 51st values) • 50th value is ‘0’ and 51st value is also ‘0’ • So median is 0
Mean …… New column on table
Mean = 45 ÷ 100 = …… 0.45
Mode = ……. 10
Range = …… 12 – 8 = 4
Median • 50 data values so do the ‘add 1 and half’ thing – we want the 25th and 26th values • Median is 10
Mean = 498 ÷ 50 = 9.96