Finding: Interquartile Range from Dot Plot

2- Mr Kim

Example on:Finding IQR for even number of scores

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Finding IQR from Dot Plots (Even number of scores)

1. Find the Median by crossing off the

dots

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Finding IQR from Dot Plots (Even number of scores)

Start by crossing off the Bottom dot

from the Smallest Score

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Finding IQR from Dot Plots (Even number of scores)

Start by crossing off the Bottom dot

from the Smallest Score

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

Now cross off the Top dot from the Biggest Score

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Finding IQR from Dot Plots (Even number of scores)

Now cross off the Top dot from the Biggest Score

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

Always cross off the dots in the directions

shown

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

So the Median (Q2) is between 6 and 6

which is 6

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Finding IQR from Dot Plots (Even number of scores)

Keep the line

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Finding IQR from Dot Plots (Even number of scores)

Now you have to find the Lower and Upper

Quartile by dividing the Dot Plot in two

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Finding IQR from Dot Plots (Even number of scores)

**It is very important to divide the sides properly

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Finding IQR from Dot Plots (Even number of scores)

To do this, count the dots from the start until you

reach the Line

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

Stop here!

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Finding IQR from Dot Plots (Even number of scores)

Now put a Border around the dots that you

just counted

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

Now put a Border around the other side

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

This is how you Correctly divide the

sides

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Finding IQR from Dot Plots (Even number of scores)

Notice there are 9 dots on each side

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Finding IQR from Dot Plots (Even number of scores)

9 here

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Finding IQR from Dot Plots (Even number of scores)

9 here

And 9 here

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Finding IQR from Dot Plots (Even number of scores)

This is the INCORRECT

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Finding IQR from Dot Plots (Even number of scores)

This is the INCORRECT

Do you notice the difference?

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Finding IQR from Dot Plots (Even number of scores)

This is the INCORRECT

There are 10 dots here

There are 8 dots here

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Finding IQR from Dot Plots (Even number of scores)

Now find the Median for both sides of the dots

by crossing off each side at a time

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Finding IQR from Dot Plots (Even number of scores)

We will start with this side (it doesn’t matter

which side)

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Finding IQR from Dot Plots (Even number of scores)

Remember the directions

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

1 2 3 4 5 6 7

Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

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Finding IQR from Dot Plots (Even number of scores)

So the Lower Quartile (Q1) is 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

Now do the same to the other side by crossing off

the scores

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

Remember the directions

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5

So the Upper Quartile (Q3) is 6

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5Upper Quartile: 6

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5Upper Quartile: 6

So, Interquartile Range:

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5Upper Quartile: 6

So, Interquartile Range:

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5Upper Quartile: 6

So, Interquartile Range:

6 -

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5Upper Quartile: 6

So, Interquartile Range:

6 -

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5Upper Quartile: 6

So, Interquartile Range:

6 - 5

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Finding IQR from Dot Plots (Even number of scores)

Lower Quartile: 5Upper Quartile: 6

So, Interquartile Range:6 - 5= 1 Our Final

Answer!