Statistics for AMC-8

This lesson is a pre-probability introduction to Statistics including representation of data and measures of central tendency.


A table is a set of facts and figures arranged in rows and columns.

Example :

 Hosts of the FIFA World Cup                                   
                                   Year Country

  2014            Brazil                                   
                                   2010            South Africa

 2006            Germany
                                    2002            South Korea / Japan
                                    1998            France
                                    1994            USA
                                    1990            Italy
                                    1986            Mexico
                                    1982            Spain
                                    1978            Argentina
                                    1974            Germany
                                    1970            Mexico
                                    1966            England
                                    1962            Chile
                                    1958            Sweden
                                    1954            Switzerland
                                    1950            Brazil

Charts and graphs

A graph is a drawing that shows the relationship between two things.
It is a diagram displaying the relationship between numbers or amounts.  Most graphs use bars, lines, or parts of a circle to display data.

Line Graph A line graph utilises two axes on a paper to show the relationship between two quantities by means of a curve.

Bar graph

A bar graph is similar to a line graph but one of the axes is not numerical.


Histogram is a bar graph where the independent axis is quantitative but divided into groups instead of individual values.


The mean is the common “average”, where all the numbers in a dataset are added up and divided by the number of data points.


The median of a dataset is the “middle” value in the list of numbers. To find the median, it is necessary to list the numbers in numerical order.


The mode of a dataset is the value that occurs most often. If no number in the list is repeated, then it does not exist.

Example :

Consider the list 13, 18, 13, 14, 13, 16, 14, 21, 13.

The mean is 15.

The median is 14.

The mode is 13.