Test 2

Create a professional looking html page. Include all the necessary elements of a good markdown page. Your task is to use the mtcars data to show that pie charts are less efficient than histogram when displaying data. Explain why the histogram is better. Hint.: Use of the pie() and barplot() for categorical data and hist() for continuous data functions. You might need to massage the data with table() prior to using the graphing functions. Generate the HTML page using Rmarkdown.

head(mtcars,10)
##                    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

In the mtcars dataframe, wt seems to be continuous and cyl categorical. When trying to visualize weight (mtcars$wt) with pie chart,

pie(table(findInterval(mtcars$wt,c(1,2,3,4,5,6,7,8))),border = "black")
box()

On the other hand, a histogram can present a view that emphasises the proportion better than a pie chart

hist(mtcars$wt,labels = TRUE,border = "black", main="Histogram of Weight range of cars",xlab = "Weight Range", col = "turquoise")

mtcars$cyl contains categorical data that points at the number of cylinders in the engine. To represent this visually, barplots can be used rather than pie charts.

pie(table(findInterval(mtcars$cyl,c(1,2,3,4,5,6,7,8))),border = "black", main="Pie chart of share of cars with 4,6 and 8 cylinders")
box()

### The barplot however can be a more effective way of visualization of mtcars$cyl

barplot(table(findInterval(mtcars$cyl,c(1,2,3,4,5,6,7,8))),border = "black", main="Bar Plot of number of cars with 4,6 and 8 cylinders", col = "cyan")

Therefore barplots and histograms can give a more informative form of data visualization compared to piecharts.