# Maths unit A:Grouped frequency diagrams, polygons and averages

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• Created by: rvsn
• Created on: 16-11-14 20:45
How do you draw a grouped frequency diagram?
Like a normal bar hart but with no gaps
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How do you draw a grouped frequency polygon?
Plot the midpoints of each bar/piece of grouped data, then plot it against the frequency like normal and join the dots to make a line
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How do you work out the estimate of the mean?
1. create midpoint(x) column 2. create fx column(frequency x midpoint) 4. total fx/total frequency=approximate answer (draw wobbly equals sign for this)
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How do you work out the modal class/group?
The group with the highest frequency is the modal class/group
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How do you work out the median class/group?
1. (total frequency+1)/2 2. This gives us the position 3.We do cumulative frequency until we get on or above the median value position 4. The group that this value is in is the median class/group
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## Other cards in this set

### Card 2

#### Front

How do you draw a grouped frequency polygon?

#### Back

Plot the midpoints of each bar/piece of grouped data, then plot it against the frequency like normal and join the dots to make a line

### Card 3

#### Front

How do you work out the estimate of the mean?

### Card 4

#### Front

How do you work out the modal class/group?

### Card 5

#### Front

How do you work out the median class/group?

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