Question 1 Answers:

#Declaring Vectors
a <- c(2, 5, 6, 7)
b <- c(1, 0, 9, 8)
c <- c(6, 5, 8, 3)

#Creating matrix (3x4)
matrix <- rbind(a, b, c)

#Setting Column Name
colnames(matrix) <- c("Mon", "Tue", "Wed", "Thu")

#Setting Row Name
rownames(matrix) <- c("Present", "Absent", "On Leave")

matrix
##          Mon Tue Wed Thu
## Present    2   5   6   7
## Absent     1   0   9   8
## On Leave   6   5   8   3
rowSums <- rowSums(matrix)

rowSums
##  Present   Absent On Leave 
##       20       18       22
colSums <- colSums(matrix)

colSums
## Mon Tue Wed Thu 
##   9  10  23  18

Question 2 Answers:

#Declaring Dataset
data <- mtcars

#Assigning variables
Displacement <- data$disp
Miles_per_Gallon <- data$mpg
gear <- data$gear

data
##                      mpg cyl  disp  hp drat    wt  qsec vs am gear carb
## Mazda RX4           21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
## Mazda RX4 Wag       21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
## Datsun 710          22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
## Hornet 4 Drive      21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
## Hornet Sportabout   18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
## Valiant             18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
## Duster 360          14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
## Merc 240D           24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
## Merc 230            22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
## Merc 280            19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4
## Merc 280C           17.8   6 167.6 123 3.92 3.440 18.90  1  0    4    4
## Merc 450SE          16.4   8 275.8 180 3.07 4.070 17.40  0  0    3    3
## Merc 450SL          17.3   8 275.8 180 3.07 3.730 17.60  0  0    3    3
## Merc 450SLC         15.2   8 275.8 180 3.07 3.780 18.00  0  0    3    3
## Cadillac Fleetwood  10.4   8 472.0 205 2.93 5.250 17.98  0  0    3    4
## Lincoln Continental 10.4   8 460.0 215 3.00 5.424 17.82  0  0    3    4
## Chrysler Imperial   14.7   8 440.0 230 3.23 5.345 17.42  0  0    3    4
## Fiat 128            32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
## Honda Civic         30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
## Toyota Corolla      33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
## Toyota Corona       21.5   4 120.1  97 3.70 2.465 20.01  1  0    3    1
## Dodge Challenger    15.5   8 318.0 150 2.76 3.520 16.87  0  0    3    2
## AMC Javelin         15.2   8 304.0 150 3.15 3.435 17.30  0  0    3    2
## Camaro Z28          13.3   8 350.0 245 3.73 3.840 15.41  0  0    3    4
## Pontiac Firebird    19.2   8 400.0 175 3.08 3.845 17.05  0  0    3    2
## Fiat X1-9           27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
## Porsche 914-2       26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
## Lotus Europa        30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2
## Ford Pantera L      15.8   8 351.0 264 4.22 3.170 14.50  0  1    5    4
## Ferrari Dino        19.7   6 145.0 175 3.62 2.770 15.50  0  1    5    6
## Maserati Bora       15.0   8 301.0 335 3.54 3.570 14.60  0  1    5    8
## Volvo 142E          21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2

2.A

Scatterplot of mpg vs disp

Scatterplot without ggPlot2
#Scatter Plot
plot(Displacement, Miles_per_Gallon, main = 'Displacement vs Miles Per Gallon', xlab = 'Displacement', ylab = 'Miles Per Gallon', cex = 1)
abline(v = seq(100, max(Displacement), by = 100) , h = seq(min(Miles_per_Gallon), max(Miles_per_Gallon), by = 5), col = "gray", lty = "dotted")

Scatterplot With ggPlot2
# Using ggplot2 library
library(ggplot2)

plot <- ggplot(data, aes(x=Displacement, y=Miles_per_Gallon)) 
plot + 
  geom_point(color = "chartreuse", fill = "deepskyblue4", size = 3) + 
  geom_point(shape = 1,size = 3,colour = "deeppink") +
  labs(x = "Displacement", y = "Miles per Gallon", title = 'Displacement vs Miles Per Gallon' ) + 
  theme(
    plot.title = element_text(color="darkolivegreen", size=16, face="bold", hjust = 0.5),
    axis.title.x = element_text(color="darkslategrey", size=14, face="bold"),
    axis.title.y = element_text(color="#993333", size=14, face="bold"),
    plot.background = element_rect(fill = "gray90"),
    panel.background = element_rect(fill = "black"),
    panel.grid.major = element_line(color = "blue3"),
    panel.grid.minor = element_blank(),
    axis.line = element_line(color = "cyan"),
    axis.text = element_text(color = "black", face="bold")
  )

2.B

Boxplot of mpg with gear

Boxplot Without ggPlot2
boxplot(Miles_per_Gallon ~ gear, data = mtcars, main = "Mpg with Gear Boxplot", xlab = "Gear", ylab = "Miles per Gallon")

Boxplot With ggPlot2
library(ggplot2)

plot <- ggplot(mtcars, aes(x = factor(gear), y = Miles_per_Gallon))
  plot +
  geom_boxplot(color = "chartreuse", fill = "deepskyblue4") +
  labs(title = expression(underline("Mpg with Gear Boxplot")), x = "Gear", y = "Miles per Gallon") +
  theme(
    plot.title = element_text(color="darkolivegreen", size=16, hjust = 0.5),
    axis.title.x = element_text(color="darkslategrey", size=14, face="bold"),
    axis.title.y = element_text(color="#993333", size=14, face="bold"),
    plot.background = element_rect(fill = "gray90"),
    panel.background = element_rect(fill = "black"),
    panel.grid.major = element_line(color = "blue3"),
    panel.grid.minor = element_blank(),
    axis.line = element_line(color = "cyan"),
    axis.text = element_text(color = "black", face="bold")
  )

2.C

Histogram of disp

#number of observations
num_observations = nrow(data)

# Calculating the total number of bins using the square root rule
num_bins <- ceiling(sqrt(num_observations))

# Calculating the bin width using Scott's rule
bin_width <- 3.5 * sd(Displacement) / num_observations
Histogram Without ggPlot2
hist(Displacement, breaks = seq(min(Displacement), max(Displacement) + bin_width, by = bin_width), main = "Histogram of Displacement", xlab = "Displacement", ylab = "Frequency")

Histogram With ggPlot2
library(ggplot2)

ggplot(mtcars, aes(x = disp)) +
  geom_histogram(binwidth = bin_width, breaks = seq(min(Displacement), max(Displacement) + bin_width, by = bin_width), color = "chartreuse", fill = "deepskyblue4") +
  labs(title = "Histogram of Displacement", x = "Displacement", y = "Frequency") +
  theme(
    plot.title = element_text(color = "darkolivegreen", size = 16, hjust = 0.5, face = "bold"),
    axis.title.x = element_text(color = "darkslategrey", size = 14, face = "bold"),
    axis.title.y = element_text(color = "#993333", size = 14, face = "bold"),
    plot.background = element_rect(fill = "gray90"),
    panel.background = element_rect(fill = "black"),
    panel.grid.major = element_line(color = "blue3"),
    panel.grid.minor = element_blank(),
    axis.line = element_line(color = "cyan"),
    axis.text = element_text(color = "black", face = "bold")
  )