Representing Data Sets ~Adapted from Walch Education
Slide 3
Dot Plots, Histograms, and Box Plots, Oh My! u Dot plots and
histograms show the frequency of a data value. u In a dot plot,
each data value is represented by a dot. The number of times a
value is repeated corresponds to the number of dots above that
value. u In a histogram, the height of a rectangle above a value
corresponds to the number of data values with that value.
Slide 4
Continued u A box plot shows the minimum, maximum, first
quartile, median, and third quartile of numerical data. The middle
50% of the data is represented with a box u A box plot shows the
range of data in a data set, and measures of center can be easily
seen on a box plot. u Box plots can be used to compare expected
values of multiple data sets.
Slide 5
What should I use, and when? A box plot shows more information
about the expected value of a data set than a dot plot or
histogram. A dot plot or histogram provides information about the
size of a data set, which cannot be seen in a box plot.
Slide 6
Practice Problemthis one you need to bring to class tomorrow u
A pharmacy records the number of customers each hour that the
pharmacy is open. The staff is using the information to determine
how many people need to be working at the pharmacy at each time of
day. The number of customers is in the table on the next slide. Use
the table to create a histogram to help the pharmacy staff
understand how many customers are in the pharmacy at each time of
day.
Slide 7
RememberIn a histogram, a rectangle is drawn above each value
in a data set. The height of each rectangle corresponds to the
number of data points with that value.