Questions

Find the mtcars data in R. This is the dataset that you will use to create your graphics.

  1. Create a pie chart showing the proportion of cars from the mtcars data set that have different carb values and write a brief summary.
pie(table(mtcars$carb),main='Pie Chart of carb')

# Based on the chart we can see that cars with carb 1, 2 and 4 are the three biggest proportion of the dataset. 3,6 and 8 are just small parts.
  1. Create a bar graph, that shows the number of each gear type in mtcarsand write a brief summary.
barplot(table(mtcars$gear),main="Gear Distribution",xlab='Number of Gears')

# Most cars are with 3 or 4 gears while car with 5 gears are relatively small portion of the dataset
  1. Next show a stacked bar graph of the number of each gear type and how they are further divided out by cyland write a brief summary.
Counts <- table(mtcars$cyl, mtcars$gear)
barplot(Counts,main='Car Distribution by Gears and Cyl',xlab='Number of Gears', col=c("yellow","green",'black'),legend = rownames(Counts))

# For 3 gear cars, most of them carry 8 cylinders. For 4 gear cars, most of them carry 4 cylinder. For 5 gear cars, the chance to got 4 cylinders or 8 cylinders are roughly the same
  1. Draw a scatter plot showing the relationship between wt and mpgand write a brief summary.
plot(mtcars$wt, mtcars$mpg, main="Scatterplot of wt and mpg", 
    xlab="Car Weight ", ylab="Miles Per Gallon ", pch=19)

# Their is a negative relationship between car weight and MPG. The more the car weights, the lower the MPG it will has.
  1. Design a visualization of your choice using the data and write a brief summary about why you chose that visualization.
plot(mtcars$hp, mtcars$mpg, main="Scatterplot of hp and mpg", 
    xlab="Horse Power ", ylab="Miles Per Gallon ", pch=20)

# This scatterplot shows the relationship between horse power of the car and MPG. So basically most of the environmental friendly cars are the ones which have lower house power.