1. ©G Dear 2010 – Not to be sold/Free to use
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Data Sets
Applied Mathematic
(Preliminary General 1)
Range and IQR
With Stem-and-Leaf
Stage 6 - Year 11$
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©G Dear 2010 – Not to be sold/Free to use

2. Interquartile Range = Q3 – Q1
Stem-and-Leaf Plots & the IQR.
Interquartile Range = Q3 – Q1
Stem Leaf 1 2 3
First find median. 4 5 6 7
There are 27 scores. 8 9 10 11 12
Median = 14th score.
(The middle score.) 13 14 15 16 17 18 19 20 21 22 23
Median = 32. 24 25 26 27
End of
Slide

3. Interquartile Range = Q3 – Q1
Stem-and-Leaf Plots & the IQR.
Interquartile Range = Q3 – Q1
Stem Leaf 1 2 3
Now find Q1. 4 5 6 7
There are 13 scores in the lower half. 8 9 10 11 12 13 14
Q1 = 7th score.
(The middle score.)
Q1 = 15.
End of
Slide

4. Interquartile Range = Q3 – Q1
Stem-and-Leaf Plots & the IQR.
Interquartile Range = Q3 – Q1
Stem Leaf
Next find Q3. 7
There are 13 scores in the upper half. 1 14 15 16 2 17 3 18 4
Q3 = (14+7)st score.
(The middle score.) 5 19 20 7 21 8 9 6 10 11 12 13
Q3 = 44.
21st score
End of
Slide

5. Interquartile Range = Q3 – Q1
Stem-and-Leaf Plots & the IQR.
Interquartile Range = Q3 – Q1
Stem Leaf
IQR = 44
- 15 7
= 29 14
Range = 52
- 1 21
= 51
End of
Slide

6. Interquartile Range = Q3 – Q1
Stem-and-Leaf Plots & the IQR.
Interquartile Range = Q3 – Q1
Stem Leaf
5 2
Median =
= (21+23)÷2
= 22
Q1 =
= 9
Q3 =
= 34
IQR =
= 25
Range =
= 52
- 3
= 49
End of
Show