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summary(cars)
##      speed           dist       
##  Min.   : 4.0   Min.   :  2.00  
##  1st Qu.:12.0   1st Qu.: 26.00  
##  Median :15.0   Median : 36.00  
##  Mean   :15.4   Mean   : 42.98  
##  3rd Qu.:19.0   3rd Qu.: 56.00  
##  Max.   :25.0   Max.   :120.00

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Note that the echo = FALSE parameter was added to the code chunk to prevent printing of the R code that generated the plot. ## Questions

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

  1. Create a pie chart using ggplot showing the proportion of cars from the mtcars data set that have different cylinder (cyl) values.
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.   :8.000
pie(mtcars$carb)

  1. Create a bar graph using ggplot, that shows the number of each carb type in mtcars.
barplot(mtcars$carb,main = "Frequency of Carb",xlab="Carb",col=c("green"))

  1. Next show a stacked bar graphusing ggplot of the number of each gear type and how they are further divided out by cyl.
frq<-table(mtcars$cyl,mtcars$gear)
barplot(frq,main="Distribution of cyl & gear",xlab="Number of gears",col=c("blue","darkblue","lightblue"),legend=rownames(frq))

  1. Draw a scatter plot using ggplot showing the relationship between wt and mpg.
plot(mtcars$wt,mtcars$mpg,main="Scatterplot Example",xlab="Car Weight",ylab="Miles Per Gallon",pch=19,col=c("green"))

  1. Design a visualization of your choice using ggplot using the data and write a brief summary about why you chose that visualization.

Use correlation plot to show correlation relationship between factors. We can see that mpg and wt has negative correlation.

library("corrplot")
## corrplot 0.84 loaded
corrplot(cor(mtcars))