Data Analysis Check-up Lesson #1

Purpose:  To learn terms and look at line plots.

Concepts

So, here are the concepts:
mean, median, and mode       cruise through this site to familiarize yourself with the terms.

2.
Range   = The variation between the lowest value in the data set and the highest value in the set.  In my example below, the range of the number of members in the House of Representatives is from 2 to 52.

3.
Line Plot = First type of graph to be studied.  Line plots are a way to show a relatively small number of data points.  Usually there will be 25 or fewer pieces of data shown on a line plot.  A number line is marked off in regular increments and values that are the same or nearly the same are labeled one above the other.  A line plot actually looks like a bar graph with all data points shown.  From a line plot one can easily see the range, mode, outliers, clusters, and gaps of a data set.

Here is some data and a line plot to help point out some more of the concepts that must be understood. 4.      Outliers        = data values that are substantially larger or smaller than the other values.
In my example, California has 52 representatives.  This number of representatives
is very different from the rest.
5.      Gaps            = large spaces between points.
In my example, there is a gap between the two states that have around 30
representatives (New York and Texas) and California with 52 representatives.
6.      Clusters        = isolated groups of points.
In my example, most of the states seem to have between 2 and 12 representatives
= cluster.
7.      Extremes        = The highest and lowest values of a data set.
In my example, many states have two representatives but no states have less
than 2.  So, 2 is one of my extremes.  The high extreme is California with 52
representatives.