Lab 11 (4/2/15)

For this lab, you will use R Markdown and knitr to recreate this report exactly, including this paragraph. Specifically, use the mtcars dataset in R to recreate the English text, table, and figure you see here in an html file like this one. Note: All the results printed in the “Introduction” section should be created using in-line R code. Remember to:

Introduction

The R dataset mtcars has 11 variables and 32 observations. The average fuel consumption reported was 20.09 mpg with a standard deviation of 6.03. The average horsepower was 146.69 (sd=68.56).

In this report, we create:

  1. A table displaying means for each variable by transmission type
  2. A scatterplot of miles per gallon (MPG) and horsepower by transmission type

Table

# Make transmission a factor variable
mtcars$am <- factor(mtcars$am, levels = c(0,1), labels = c("automatic", 
  "manual"))
# Group data by transmission
gcars <- group_by(mtcars, am)
# Get means for each variable
t1 <- summarise_each(gcars, funs(mean(., na.rm = T)), mpg, disp : qsec)
# Print knitr table
kable(t1, digits = 2, 
  caption = "Means of Fuel Consumption and Auto Design Elements")
Means of Fuel Consumption and Auto Design Elements
am mpg disp hp drat wt qsec
automatic 17.15 290.38 160.26 3.29 3.77 18.18
manual 24.39 143.53 126.85 4.05 2.41 17.36

Figure