Presentation And Analysis

A specimen Extension paper shows a cumulative frequency graph somebody has drawn from a table of examination marks and asks for two criticisms of it. Not for a calculation, not for a value: for two things the person did wrong. The answers the mark scheme wants are that one cumulative total should be 48 rather than 46, and that the points should be plotted at the ends of the class intervals. That is what this topic is really about: handling data correctly enough that the picture you draw tells the truth.

You will classify data as qualitative, discrete or continuous and as grouped or ungrouped, extract data from printed tables and lists, design and use two-way tables, produce the full range of charts and diagrams from tally charts and pictograms to frequency polygons and histograms with equal class intervals, and calculate the median, mean, range, mode and modal class. On the Extension Tier you add histograms with unequal class intervals, cumulative frequency diagrams, box plots, quartiles, the inter-quartile range and percentiles.