Data Visualization in R
Solutions to Hands On Exercises
L. Torgo
[email protected]
Faculdade de Ciências / LIAAD-INESC TEC, LA
Universidade do Porto
Oct, 2016
Hands on Data Visualization - the Algae data set
Using the Algae data set from package DMwR answer to the following
questions:
1
Create a graph that you find adequate to show the distribution of
the values of algae a6 solution
2
Show the distribution of the values of size
3
Check visually if it is plausible to consider that oPO4 follows a
normal distribution solution
© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
solution
Oct, 2016
2 / 10
Solution of Exercise 1
Create a graph that you find adequate to show the distribution of
the values of algae a6
hist(algae$a6,main="Distribution of Algae a6",xlab="Frequency of a6",
ylab="Nr. of Occurrences")
100
50
0
Nr. of Occurrences
150
Distribution of Algae a6
0
20
40
60
80
Frequency of a6
© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
Oct, 2016
3 / 10
Solution of Exercise 1 with ggplot2
Create a graph that you find adequate to show the distribution of
the values of algae a6
ggplot(algae,aes(x=a6)) + geom_histogram(binwidth=10) +
ggtitle("Distribution of Algae a6")
Distribution of Algae a6
150
count
100
50
0
0
25
50
75
a6
Go Back
© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
Oct, 2016
4 / 10
Solution to Exercise 2
Show the distribution of the values of size
barplot(table(algae$size), main = "Distribution of River Size")
0
20
40
60
80
Distribution of River Size
large
© L.Torgo (FCUP - LIAAD / UP)
medium
Data Visualization
small
Oct, 2016
5 / 10
Solution to Exercise 2 with ggplot2
Show the distribution of the values of size
ggplot(algae,aes(x=size)) + geom_bar() +
ggtitle("Distribution of River Size")
Distribution of River Size
80
count
60
40
20
0
large
medium
small
size
Go Back
© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
Oct, 2016
6 / 10
Solutions to Exercise 3
Check visually if it is plausible to consider that oPO4 follows a
normal distribution
library(car)
qqPlot(algae$oPO4,main = "QQ Plot of oPO4")
QQ Plot of oPO4
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100
algae$oPO4
400
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−2
−1
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norm quantiles
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© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
Oct, 2016
7 / 10
Hands on Data Visualization - Algae data set
Using the Algae data set from package DMwR answer to the following
questions:
1
Produce a graph that allows you to understand how the values of
NO3 are distributed across the sizes of river solution
2
Try to understand (using a graph) if the distribution of algae a1
varies with the speed of the river solution
© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
Oct, 2016
8 / 10
Solutions to Exercise 1
Produce a graph that allows you to understand how the values of
NO3 are distributed across the sizes of river.
ggplot(algae,aes(x=NO3)) + geom_histogram(binwidth=5) + facet_wrap(~size)
ggtitle("Distribution of NO3 for different river sizes")
Distribution of NO3 for different river sizes
large
medium
small
60
count
40
20
0
0
20
40
0
20
40
0
20
40
NO3
Go Back
© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
Oct, 2016
9 / 10
Solutions to Exercise 2
Try to understand (using a graph) if the distribution of algae a1
varies with the speed of the river
ggplot(algae,aes(x=speed,y=a1)) + geom_boxplot() +
ggtitle("Distribution of a1 for different River Speeds")
Distribution of a1 for different River Speeds
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a1
50
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0
high
low
medium
speed
Go Back
© L.Torgo (FCUP - LIAAD / UP)
Data Visualization
Oct, 2016
10 / 10