* Complete the following in R. ALL work must be done in R.
Column 1: sl: The three month salary of the subject in dollars (Y ).
Column 2: yd: The number of years since the subject earned their highest degree (X1) (i.e., years of experience).
Column 3: dg: The highest degree earned (doctorate, masters) of the subject (X2).
Column 4: sx: The gender of the subject (male, female) (X3)
Column 5: rk: The rank of the subject (assistant, associate, full) (X4)