12.2 Stem-and-Leaf Plots, 12.2 Stem-and-Leaf Plots, Histograms, and Circle Histograms, and Circle

GraphsGraphs

Objectives: Make a stem-and-leaf plot, a histogram, or a Objectives: Make a stem-and-leaf plot, a histogram, or a circle graph for a data set. circle graph for a data set.

Find and use relative frequencies to solveFind and use relative frequencies to solve probability problems.probability problems.

Standards: 2.6.5A Organize and display data using Standards: 2.6.5A Organize and display data using pictures, tallies, tables, charts, bar pictures, tallies, tables, charts, bar

and circle graphs. 2.6.8E Analyze and display and circle graphs. 2.6.8E Analyze and display data in a stem-and-leaf plot.data in a stem-and-leaf plot.

I. A stem-and-leaf plot of the Internet data is shown below. A stem-and-leaf plot is

a quick way to arrange a set of data and view its shape, or general distribution.

In a stem-and-leaf plot each data value is split into 2 parts: a stem and leaf.

*Ex 1. Colby is planning the annual Smith family reunion. She has collected the ages of the family members who plan to

attend.a). Make a stem-and-leaf plot of the ages.b). Find the median and mode of the ages.

c). How can the stem-and-leaf plots be used to plan the reunion?

Stem Leaf

0123456789

*Ex2. A bakery collected the following data about the # of loaves of bread sold each of the 24 business days:

53, 49, 27, 48, 60, 52, 44, 38, 47, 52, 82,46, 55, 31, 39, 54, 51, 47, 50, 45, 50, 61, 43, and 64.

Make a stem-and-leaf plot of the data. Find the median and mode(s) of the data.

How can the owner use the stem-and-leaf plot to make plans for baking bread?

Stem Leaf

II. Histogram – a bar graph that gives the frequency of each value. In a histogram, the horizontal axis

is like a number line divided into equal widths. Each width represents

a data value or range of data values. The height of each bar indicates the frequency of

that data value or range of data values.

*Ex 2. The given data shows the # of people in 24 vehicles hat passed a designated checkpoint.

1, 4, 1, 2, 2, 1, 3, 1, 3, 2, 2, 6, 4, 2, 1, 1, 2, 4, 3, 1, 2, 4, 2, 3.

Make a frequency table for these data. Make a histogram from the frequency table.

## FrequencyFrequency

11

22

33

44

55

66

III. Relative Frequency Tables – frequency tables that include a column that displays

how frequently a value appears relative to the entire data set. The relative frequency

column is the % frequency, or probability. A relative frequency table and histogram are shown below for the canoe rental data.

*Ex1. Use the relative frequencies given above to estimate the probability that randomly selected

customer will rent a canoe for 5 or more hours.

What % rented a canoe for 5, 6, 7, and 8 hours?

IV.Circle Graphs –

display the distribution of

non-overlapping parts of a whole

*Ex 2. The table below shows the distribution by region of the resident population of the

U.S. in 1996. a). Make a circle graph to represent the data.

b). Find the probability that a randomly chosen resident of the U.S. in 1996 wasn’t a

resident of the South.

RegionRegion PopulationPopulation

(In millions)(In millions)

Relative Relative FrequencyFrequency

NENE 51.651.6

MidwestMidwest 62.162.1

SoutSout 93.193.1

WestWest 58.558.5

Writing ActivitiesWriting Activities

Review of Stem-and-Leaf Plots, Review of Stem-and-Leaf Plots, Histograms, and Circle GraphsHistograms, and Circle Graphs