This section uses the raw
depression data set from the Afifi et.al. textbook. This is a tab-delimited data set, so we opt to use
read.table here. We include arguments
sep="\t" to indicate columns are separated with tabs and
header=TRUE to indicate the first row of the data is the variable names.
The absolute first thing you should do is to look at your raw data table. Are the column headers variable names? Did all the rows get read in? Are there any extra columns or rows included?