Review: data and combinatorics

We present data with tables and diagrams: a bar chart compares values, a line graph shows change, a pie chart shows the parts of a whole (the whole circle is 360° and a p% sector is 360° · p : 100). For a list of numbers: the mean is sum : count; the range is largest − smallest; the mode is the number occurring most often; the median is the middle of the ordered list. In combinatorics, ways add (m + n) in “either-or” situations and multiply (m · n) in “both ... and” situations.