12.2 Stem-and-Leaf Plots, Histograms, and Circle Graphs 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 solve Find and use relative frequencies to solve probability problems. probability problems. Standards: 2.6.5A Organize and display data using pictures, tallies, tables, charts, bar and circle graphs E Analyze and display data in a stem-and-leaf plot. and circle graphs E Analyze and display data in a stem-and-leaf plot.

I. A stem-and-leaf plot of 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? StemLeaf

*Ex2. A bakery collected the following data about the # of loaves of bread sold on each of 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. a.) Make a stem-and-leaf plot of the data. b.) Find the median and mode(s) of the data. c.) How can the owner use the stem-and-leaf plot to make plans for baking bread? StemLeaf

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 that 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. a.) Make a frequency table for these data. b.) Make a histogram from the frequency table. #Frequency

III.Relative Frequency Table – a frequency table that includes a column that displays how frequently a value appears relative to the entire data set. The relative frequency column is the % frequency, or probability.

*Ex1. Use the relative frequencies given to estimate the probability that a randomly selected customer will rent a canoe for 5 or more hours. Question: What % rented a canoe for 5, 6, 7, and 8 hours? HoursFrequencyRelative Frequency 133/30 = 0.10 = 10% Total30

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 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. RegionPopulation (In millions) Relative Frequency NE51.6 Midwest62.1 South93.1 West58.5

Writing Activities

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

Homework Integrated Algebra II- Section 12.2 Level A Academic Algebra II- Section 12.2 Level B Circle graph to be done on circle handed out in class.