Go through topics/concepts as per following link:
http://www.cssforum.com.pk/191160-post16.html
In addition to these linked questions revise some basic concepts of statistics like: Standard Deviation, coefficient of correlation, variances, regression analysis, probability, normal distribution, sampling, hypothesis, averages / mean (simple arithmetic, geometric, harmonic), mode, median.
Just understand these concepts and you should be able to define these terms along with their practical usage. You would not be required to solve any problems or narrate formulae.