Statistics 2.2: More Graphs and Displays
Objective 1: I can graph quantitative data sets.
In 2.1, you learned several traditional ways to display quantitative data graphically. In this section, you will learn ways to display the data so that you can see ALL the individual data values.
*Stem-and-Leaf Plot
A ______is a display that separates each data value into a stem, the ______digits and a leaf, the ______digit. A stem-and-leaf plot is similar to a ______except you can see all the data entries. A stem-and-leaf plot is also an easy way to ______.
Read Example 1, page 55
TIY 1: The following sample data set lists the number of minutes that 50 Internet subscribers spent on the Internet during their most recent session. Construct a stem-and-leaf plot of the data.
50 40 41 17 11 7 22 44 28 21 19 23 37
54 42 86 41 78 56 72 56 17 7 69 30 80
33 46 31 39 20 18 29 34 59 73 77 36 39
62 54 67 39 31 53 44 56 51 29 30
*Read Example 2, page 56
TIY 2: Using two rows for each stem, revise the stem-and-leaf plot you constructed in TIY 1.
This is called a ______.
*Dot Plot
Another type of graph we can use for ______, and that shows ______data value is called a ______. In a dot plot, each data entry is plotted, using a point, above a horizontal axis (basically a ______). This allows us to easily see patterns and see where the majority of data lie. It is important that each row of dots be the same height.
*Read Example 3, page 57
TIY 3: Use a dot plot to graph the data from TIY 1.
Objective 2: I can graph qualitative data sets.
We have many ways that we can display qualitative data—this is data that is non-______.
*Pie charts: A ______is also called a ______, and shows the portion, or ______, of data out of the whole. It’s important to know how to construct a pie chart by hand. (It’s on the ACT.)
Example 4: The frequency distribution below shows the number of people killed in crashes in 2005. Create a pie chart to display the data.
TIY 4: Create a pie chart to show the number of people killed in crashes in 1995. Compare the 1995 data with the 205 data above.
Another way to graph qualitative data is to use a ______chart. A Pareto chart is a bar graph in which the bars are ordered from ______to ______frequency.
*Read Example 5, page 59
TIY 5: Every year, the Better Business Bureau (BBB) receives complaints from customers. In a recent year, the BBB received the following complaints. Use a Pareto chart to organize the data.
7792 complaints about home furnishing stores
5733 complaints about computer sales and service stores
14,688 complaints about auto dealers
9728 complaints about auto repair shops
4649 complaints about dry cleaning companies
Objective 3: Graphing Paired Data Sets
When each entry in a data set corresponds to another entry, the sets are called ______sets. An example of a paired data set is a scatter plot, in which we graph ordered pairs (x, y) to see if there is a ______between the data values. When the graphed points appear to form a ______, we say there is some type of relationship and this allows us to make an ______about the data.
*Read Example 6, page 60
TIY 6: The lengths of employment and the salaries of 10 employees are shown in the table below. Graph the data using a scatter plot. What can you conclude?
Another great way to display paired data is with a ______chart. This is used to measure the change of a specific variable over time. Generally we put the time, ______, on the horizontal axis and the quantitative data on the vertical axis.
*Read Example 7, page 61.
TIY 7: Use the table in Example 7 to construct a time series chart for a subscriber’s average local monthly cell phone bill for the years 1995 through 2005. What can you conclude?