Session 4_Apurva_PGP32242
Apurva
18 September 2017
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First few rows of data
head(mtcars) ## mpg cyl disp hp drat wt qsec vs am gear carb
## Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
## Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
## Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
## Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
## Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
## Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1Summary of the data
summary(mtcars) ## mpg cyl disp hp
## Min. :10.40 Min. :4.000 Min. : 71.1 Min. : 52.0
## 1st Qu.:15.43 1st Qu.:4.000 1st Qu.:120.8 1st Qu.: 96.5
## Median :19.20 Median :6.000 Median :196.3 Median :123.0
## Mean :20.09 Mean :6.188 Mean :230.7 Mean :146.7
## 3rd Qu.:22.80 3rd Qu.:8.000 3rd Qu.:326.0 3rd Qu.:180.0
## Max. :33.90 Max. :8.000 Max. :472.0 Max. :335.0
## drat wt qsec vs
## Min. :2.760 Min. :1.513 Min. :14.50 Min. :0.0000
## 1st Qu.:3.080 1st Qu.:2.581 1st Qu.:16.89 1st Qu.:0.0000
## Median :3.695 Median :3.325 Median :17.71 Median :0.0000
## Mean :3.597 Mean :3.217 Mean :17.85 Mean :0.4375
## 3rd Qu.:3.920 3rd Qu.:3.610 3rd Qu.:18.90 3rd Qu.:1.0000
## Max. :4.930 Max. :5.424 Max. :22.90 Max. :1.0000
## am gear carb
## Min. :0.0000 Min. :3.000 Min. :1.000
## 1st Qu.:0.0000 1st Qu.:3.000 1st Qu.:2.000
## Median :0.0000 Median :4.000 Median :2.000
## Mean :0.4062 Mean :3.688 Mean :2.812
## 3rd Qu.:1.0000 3rd Qu.:4.000 3rd Qu.:4.000
## Max. :1.0000 Max. :5.000 Max. :8.000Description of the Data
attach(mtcars)
library(psych)
describe(mtcars) ## vars n mean sd median trimmed mad min max range skew
## mpg 1 32 20.09 6.03 19.20 19.70 5.41 10.40 33.90 23.50 0.61
## cyl 2 32 6.19 1.79 6.00 6.23 2.97 4.00 8.00 4.00 -0.17
## disp 3 32 230.72 123.94 196.30 222.52 140.48 71.10 472.00 400.90 0.38
## hp 4 32 146.69 68.56 123.00 141.19 77.10 52.00 335.00 283.00 0.73
## drat 5 32 3.60 0.53 3.70 3.58 0.70 2.76 4.93 2.17 0.27
## wt 6 32 3.22 0.98 3.33 3.15 0.77 1.51 5.42 3.91 0.42
## qsec 7 32 17.85 1.79 17.71 17.83 1.42 14.50 22.90 8.40 0.37
## vs 8 32 0.44 0.50 0.00 0.42 0.00 0.00 1.00 1.00 0.24
## am 9 32 0.41 0.50 0.00 0.38 0.00 0.00 1.00 1.00 0.36
## gear 10 32 3.69 0.74 4.00 3.62 1.48 3.00 5.00 2.00 0.53
## carb 11 32 2.81 1.62 2.00 2.65 1.48 1.00 8.00 7.00 1.05
## kurtosis se
## mpg -0.37 1.07
## cyl -1.76 0.32
## disp -1.21 21.91
## hp -0.14 12.12
## drat -0.71 0.09
## wt -0.02 0.17
## qsec 0.34 0.32
## vs -2.00 0.09
## am -1.92 0.09
## gear -1.07 0.13
## carb 1.26 0.29Summary of subset of the data
summary(mtcars$mpg)## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 10.40 15.42 19.20 20.09 22.80 33.90Mean of subset of data
mean(mtcars$mpg) ## [1] 20.09062Histogram
hist(mtcars$mpg)
Histogram with specified number of bins
hist(mtcars$mpg,
breaks=12,
xlab="Miles Per Gallon",
main="Histogram with specified number of bins")
PDF of the dataset
p <- plot(density(mtcars$mpg))
lines(p, col="black", lwd=2)
Superimpose PDF on the histogram
hist(mtcars$mpg,
freq=FALSE,
breaks=12,
xlab="Miles Per Gallon",
main="Histogram with density curve")
lines(density(mtcars$mpg), col="red", lwd=5)
Histogram with Rug Plot
hist(mtcars$mpg,
freq=FALSE,
breaks=12,
xlab="Miles Per Gallon",
main="Histogram with rug plot")
rug(jitter(mtcars$mpg))
Box Plot
attach(mtcars)## The following objects are masked from mtcars (pos = 4):
##
## am, carb, cyl, disp, drat, gear, hp, mpg, qsec, vs, wtboxplot(mpg,data=mtcars,
main="Box Plot",
ylab="Miles Per Gallon")
Two box plots side by side
boxplot(mpg~am,data=mtcars,
main="Car Milage Data",
xlab="Number of Cylinders",
ylab="Miles Per Gallon")
Create a factor for tranmission type
mtcars$am.f <- factor(mtcars$am,
levels=c(0,1),
labels=c("Automatic","Manual"))Box Plots with number of cylinders
boxplot(mpg~cyl,data=mtcars,
main="Car Milage Data",
xlab="Number of Cylinders",
ylab="Miles Per Gallon")
Create a factor for number of cylinders
mtcars$cyl.f <- factor(mtcars$cyl,
levels=c(4,6,8),
labels=c("4-Cyl","6-Cyl","8-Cyl"))Box Plots for Transmission Type and Number of Cylinders
boxplot(mpg ~ am.f *cyl.f, data=mtcars, varwidth=TRUE,col=c("gold", "darkgreen"),
main="MPG Distribution by Auto Type",xlab="Auto Type")
Mean Plots of Transmission
library(gplots)##
## Attaching package: 'gplots'## The following object is masked from 'package:stats':
##
## lowess# Plot the mean of teeth length by dose groups
plotmeans(mtcars$mpg ~ mtcars$am.f, data = mtcars, frame = FALSE)## Warning in plot.xy(xy.coords(x, y), type = type, ...): "frame" is not a
## graphical parameter## Warning in axis(1, at = 1:length(means), labels = legends, ...): "frame" is
## not a graphical parameter## Warning in plot.xy(xy.coords(x, y), type = type, ...): "frame" is not a
## graphical parameter
Mean plots of Cylinders
library(gplots)
# Plot the mean of teeth length by dose groups
plotmeans(mtcars$mpg ~ mtcars$cyl.f, data = mtcars, frame = FALSE)## Warning in plot.xy(xy.coords(x, y), type = type, ...): "frame" is not a
## graphical parameter## Warning in axis(1, at = 1:length(means), labels = legends, ...): "frame" is
## not a graphical parameter## Warning in plot.xy(xy.coords(x, y), type = type, ...): "frame" is not a
## graphical parameter
Note that the echo = FALSE parameter was added to the code chunk to prevent printing of the R code that generated the plot.