Lab Session 0
Introduction to R Practical
Heather Turner
11 September 2017
-
Open a new script file to work in, save it as a
.R
file. (Just give it any file name you want, ending in .R) -
Download
duncan.csv
from the course website (right-click the link then choose from the context menu to save). In RStudio, click on the Import Dataset button on the Environment tab in the top-right pane. Select From CSV… and select theduncan.csv
file to import.Copy the code from the Code Preview window, before clicking the Import button to import the data. A new tab will open with a preview of the data, but before looking at this, paste your copied code into your script file.
The data are from the 1971 census of Canada, with the following variables
- occupation
-
named occupation
- education
-
average education in years
- income
-
average income in dollars
- women
-
percentage women in occupation
- prestige
-
prestige score for occupation, from earlier survey
- census
-
Canadian census occupation code
- type
-
type of occupation: bc (blue collar), prof (professional, mangerial and technical) and wc (white collar)
-
Use
summary
to get a quick summary of the variables (unless you chose a different name in the Import dialog, the data frame will be calledduncan
). You will see thattype
has been read in as a character vector. Convert this to a factor using the code belowduncan$type <- factor(duncan$type)
-
Use
summary
to get an updated summary of the data. You will see thattype
has missing values.A subset of the data can be obtained with a command of the form
subset(duncan, condition)
where
condition
is a logical vector, which isTRUE
for the rows that should be kept andFALSE
otherwise.The command
is.na(x)
will return a logical vector indicating whether each element ofx
isNA
(TRUE
) or not (FALSE
). Use such a logical vector to obtain the subset of the data for whichtype
isNA
- from this you can see which occupations are unclassified. -
Using
min
, assign the minimum proportion of women to a name. The commandx == a
will return a logical vector indicating whether each element ofx
is equal toa
(TRUE
) or not (FALSE
). Usesubset
to obtain the rows of data where the proportion of women is equal to the minimum value. Repeat the process to obtain rows corresponding to the maximum. -
Create a histogram and then a density plot of the prestige variable and compare the output. Use the code completion tools in RStudio to look at the second argument of
hist
and try modifying. -
Create a boxplot of years of education by occupation type.
-
Create a scatterplot of prestige against income. Look at the help for
log
and then create a plot of prestige against log income with base 10.