Information Management - Lab 01 
- quick overview of R
- open R, load and display data, access column and row slices
- build frequency and contingency tables
- basic statistics with built-in functions (mean, median, min, max, midrange,
  quartiles, IQR, variance, standard deviation)
- computation of the mode linking built-in functions
- data visualization (histograms, boxplot, scatter plot)
- S programming: assignments, comparisons, conditional statements, loops
- S programming: definition of functions
- Example: re-implementing the mean() function
- Homework: re-implement mean, variance, standard deviation, median; implement
  a replace(x,y,T) function to replace each occurrence of a value x with value
  y in table T