Slides for Data Analysis Lab (Second Lesson)

1. Data
Analysis
–
Lab
II
marco.braggion@unive.it

2. Source
• Most
of
these
examples
are
taken
from
R
in
Ac'on,
(a
book
by
Rob
Kabacoff
edited
by
Manning
in
2011),
that
I
recommend
to
you
not
only
for
this
course!

3. A
simple
scaKerplot
attach(mtcars)
plot(wt, mpg)
abline(lm(mpg~wt))
title("Regression of MPG on
Weight")
detach(mtcars)

4. 10
15
20
mpg
25
30
Regression of MPG on Weight
2
3
4
wt
5

5. Combining
graphs
on
one
window
attach(mtcars)
par(mfrow=c(3,1))
hist(wt)
hist(mpg)
hist(disp)
par(opar)
detach(mtcars)

6. 8
4
0
Frequency
Histogram of wt
2
3
4
5
wt
6 12
0
Frequency
Histogram of mpg
10
15
20
25
30
35
mpg
0 3 6
Frequency
Histogram of disp
100
200
300
disp
400
500

7. Combining
graphs
(II)
attach(mtcars)
par(mfrow=c(2,2)) #2 rows 2 cols
plot(wt,mpg, main="Scatterplot of wt vs. mpg")
plot(wt,disp, main="Scatterplot of wt vs disp")
hist(wt, main="Histogram of wt")
boxplot(wt, main="Boxplot of wt")

8. Scatterplot of wt vs disp
200
300
disp
20
10
100
15
mpg
25
30
400
Scatterplot of wt vs. mpg
2
3
4
5
2
3
4
wt
Histogram of wt
Boxplot of wt
4
6
3
4
2
2
0
Frequency
8
5
wt
2
3
4
wt
5
5

9. Simple
histogram
hist(mtcars$mpg)
6
4
2
0
Frequency
8
10
12
Histogram of mtcars$mpg
10
15
20
25
mtcars$mpg
30
35

10. Something
more…
• hist(mtcars$mpg,
breaks=12,
col="red",
xlab="Miles
Per
Gallon",
main="Colored
histogram
with
12
bins")

11. 4
3
2
1
0
Frequency
5
6
7
Colored histogram with 12 bins
10
15
20
25
Miles Per Gallon
30

12. Superimposing
a
normal
curve
(try
it
at
home)

13. 4
3
2
1
0
Frequency
5
6
7
Histogram with normal curve
10
15
20
25
Miles Per Gallon
30

14. Boxplot

15. 25
20
15
10
Miles Per Gallon
30
Car Mileage Data
4
6
Number of Cylinders
8

16. ScaKerplot
Matrix
Basic Scatter Plot Matrix
200
300
400
2
3
4
5
10 15 20 25 30
100
300
mpg
4.0
5.0
100
disp
4
5
3.0
drat
2
3
wt
10
15
20
25
30
3.0
3.5
4.0
4.5
5.0

17. Further
resources
R
code
school
(very
nice
intro
for
newbies):
hKp://tryr.codeschool.com/
Quick-­‐R
(Rob
Kabacoff
site):
hKp://www.statmethods.net/
R
Zps
(very
detailed):
hKp://pj.freefaculty.org/R/RZps.html
R
seek
(google-­‐like
search
bar):
hKp://www.rseek.org/