In this assignment we are going to analyse the fuel consumption of vehicles.The data was extracted from the 1974 Motor Trend US magazine, and comprises fuel consumption and 10 aspects of automobile design and performance for 32 automobiles (1973–74 models).

Variables in the data set are as follows
[, 1] mpg Miles/(US) gallon
[, 2] cyl Number of cylinders
[, 3] disp Displacement (cu.in.)
[, 4] hp Gross horsepower
[, 5] drat Rear axle ratio
[, 6] wt Weight (1000 lbs)
[, 7] qsec 1/4 mile time
[, 8] vs Engine (0 = V-shaped, 1 = straight)
[, 9] am Transmission (0 = automatic, 1 = manual)
[,10] gear Number of forward gears
[,11] carb Number of carburetors

Q1

Read mtcars.csv using fread command

Q2

Display to ‘head’ of mtcars

##                   V1  mpg cyl disp  hp drat    wt  qsec vs am gear carb
## 1:         Mazda RX4 21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
## 2:     Mazda RX4 Wag 21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
## 3:        Datsun 710 22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
## 4:    Hornet 4 Drive 21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
## 5: Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
## 6:           Valiant 18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

Q3

Set the ‘cyl’ and ‘vs’ as the keys

Q4

Calculate a new column ‘kmpl’ by multiplying mpg by 0.4251

Q5

Display mean mpg for each cyl

##    cyl       V1
## 1:   4 26.66364
## 2:   6 19.74286
## 3:   8 15.10000

Q6

Display mean mpg for each cyl and vs

##    cyl vs  meanmpg
## 1:   4  0 26.00000
## 2:   4  1 26.73000
## 3:   6  0 20.56667
## 4:   6  1 19.12500
## 5:   8  0 15.10000

Q7

Create a new data.table with only 6 cyl and vs=1 and save it as ‘cyl6vs1.rds’

Q8

Display mean qsec for cyl=6 by vs type

##    vs       V1
## 1:  0 16.32667
## 2:  1 19.21500