library(ggplot2)
library(ggthemes) 
## Warning: package 'ggthemes' was built under R version 3.4.3
summary(mpg)
##  manufacturer          model               displ            year     
##  Length:234         Length:234         Min.   :1.600   Min.   :1999  
##  Class :character   Class :character   1st Qu.:2.400   1st Qu.:1999  
##  Mode  :character   Mode  :character   Median :3.300   Median :2004  
##                                        Mean   :3.472   Mean   :2004  
##                                        3rd Qu.:4.600   3rd Qu.:2008  
##                                        Max.   :7.000   Max.   :2008  
##       cyl           trans               drv                 cty       
##  Min.   :4.000   Length:234         Length:234         Min.   : 9.00  
##  1st Qu.:4.000   Class :character   Class :character   1st Qu.:14.00  
##  Median :6.000   Mode  :character   Mode  :character   Median :17.00  
##  Mean   :5.889                                         Mean   :16.86  
##  3rd Qu.:8.000                                         3rd Qu.:19.00  
##  Max.   :8.000                                         Max.   :35.00  
##       hwy             fl               class          
##  Min.   :12.00   Length:234         Length:234        
##  1st Qu.:18.00   Class :character   Class :character  
##  Median :24.00   Mode  :character   Mode  :character  
##  Mean   :23.44                                        
##  3rd Qu.:27.00                                        
##  Max.   :44.00

Visual 1:

ggplot(mpg, aes(class)) + geom_bar(aes(fill= trans))

Visual 2:

ggplot(mpg, aes( mpg$manufacturer,mpg$hwy)) + geom_boxplot()+coord_flip()+labs(
    y = "Highway Fuel Efficiency (miles/gallon)",
    x = "Vehicle Manufacturer")

Visual 3:

ggplot(diamonds, aes(x=price,color=cut,fill=cut)) + geom_density(aes(fill=factor(cut)), alpha=0.2) +theme_economist() + scale_colour_economist() +labs(title="Diamond Price Density ", x="Diamond Price(USD)", y="Density")

Visual 4:

ggplot(iris, aes(iris$Sepal.Length,iris$Petal.Length)) + geom_point() + labs(y = "Iris Sepal Length",
    x = "Iris Petal Length", title = "Relationship between Petal and Sepal Length") + geom_smooth(method=lm)

Visual 5:

ggplot(iris, aes(iris$Sepal.Length,iris$Petal.Length, color =iris$Species)) + geom_point() + labs(y = "Iris Sepal Length",
    x = "Iris Petal Length", title = "Relationship between Petal and Sepal Length") + geom_smooth(method=lm)