Page 281 - ABCTE Study Guide_Neat

Box-and-Whisker Plots

The last type of representation of data that we’ll explore in this section is a box-and-whisker plot. A box-
and-whisker plot reveals a five-number summary of a data set. These five numbers are the mean, the
upper and lower quartiles, and the maximum and minimum values in the set.

That said, we need some more definitions.

Recall that the median of a data set is the number in the middle. Half of the values lie above it and half of
the values below it.

A quartile is one fourth of the data values in a set.

The upper quartile is the median of the upper half of the set. One fourth of the data values lie above the
upper quartile.

The lower quartile is the median of the lower half of the set. One fourth of the data values lie below the
lower quartile.

Review

• Line graphs are used to display two-variable data that changes continuously over time.
• Bar graphs are used to compare discrete (not continuous) quantities in different
categories.
• A stem-and-leaf plot is a display that organizes data to show its shape and distribution.
• A frequency table is a chart that shows the number of times that values within each
interval of a data set occur. A histogram is a bar-graph-like representation of the data in a
frequency table.
• A scatterplot is a graph, or collection of points, of two-variable numerical data.
• A box-and-whisker plot reveals the mean, the upper and lower quartiles, and the
maximum and minimum values in the set.

Probability, Permutation, and More

Lesson Objective

In the coming sections, we’ll review the ideas of population, samples, and bias, as they pertain to data. We’ll
also cover simple and compound events, and see how probability works in some different examples.

Previously Covered

On the preceding pages we reviewed how two-variable data is recorded and reported. We also brushed
up on scatterplots, box-and-whisker plots, and frequency tables.

Does That Data Mean What I Think It Means? 99% of Statisticians Don’t Think So.

In this section, we’ll look briefly at inferences that can be made from available data, assumptions that can
be made about the data, and potential sources of bias that may be inherent to the data. To do this, we
need to begin with some definitions.

A population consists of an entire set of people, places, things, etc. with something in common, like all
the men in my statistics class, all the women on the planet, single parents, adopted children, and jazz