Skills Goals: Create Dot plots, Stemplots, and Histograms, using small sets of observations.
Example of a Dot plot:
Practice Problems:1) The ages of the Oscar winners for best actor and best actress (at the time they won the award) from 1996 to 2004 are as follows: 45, 39, 59, 33, 45, 25, 42, 24, 35, 32, 46, 32, 28, 34, 42, 27, 36, and 30. Create a dot plot of these data and discuss what the display implies about the data.
2) Twenty high school students were randomly selected from a very large high school. They were asked to keep a record for a week of the number of hours they slept each night. These seven values were averaged to obtain an average night of sleep for each. The results are as follows: {9, 8, 8, 7.5, 6, 6, 4, 5.5, 7, 8, 5, 7.5, 6.5, 10, 8.5, 6.5, 5, 5.5, 7, 7.5}. Create a dot plot of these data and discuss what the display implies about the data.
Stemplots- Also known as a Stem and Leaf plot, a stem plot is a device for presenting quantitative data in a graphical format. A basic stemplot contains two columns separated by a vertical line. The left column contains the stems and the right column contains the leaves. Stemplots are useful for displaying the relative density and shape of the data, giving the reader a quick overview of distribution. They are useful for medium sets of data between 10-100.
An example of a Stem plot:
UMMMMMMM....I haven't figured out how to use the Diigo thing yet, so heres an interactive link to help you learn how to do stem and leaf plots.
http://www.wisc-online.com/Objects/ViewObject.aspx?ID=tmh1101
Practice Problems:
1) Ms. Reed's AP Physics class took a test last Thursday. Make a stem and leaf plot of the test scores given: {56, 65, 98, 82, 64, 71, 78, 77, 86, 95, 91, 59, 69, 70, 80, 92, 76, 82, 85, 91, 92, 99, 73}
2) In the month of April, the Weather Channel took the average temperature of each day for the entire month: {77, 80, 82, 68, 65, 59, 61, 57, 50, 62, 61, 70, 69, 64, 67, 70, 62, 65, 65, 73, 76, 87, 80, 82, 83, 79, 79, 71, 80, 77}. Using this data, construct a stem and leaf plot to help the Weather Channel.
Histograms- Histograms are used to plot density of data, and often for density estimation: estimating the probability density function of the underlying variable. A histogram is designed for large quantities of data. Groups of data are placed into bins.
Practice Problems:
1) Using their cosmic ray detector, teachers in the University of Rochester QuarkNet Center take counts of incident muons per minute at a given location to see if they can get a good "average" value for that place. Over the next 20 minutes, the following counts are taken: {98, 103, 104, 103, 101, 98, 99, 104, 100, 104, 98, 103, 105, 103, 102, 104, 104, 103, 99, 100}. Group the data into bins. Make a histogram using this data.
2) The following is a list of the amount of time (in minutes) that it takes various students to get to school by bus: {10, 14, 9, 14, 25, 45, 13, 21, 18, 12, 7, 16, 35, 30, 12, 26, 24,19, 11, 20}. Make a histogram using this data.
3) The following is a list of prices (in dollars) of candy found in various drug stores: {1.45, 2.20, 0.75, 1.23, 1.25, 1.25, 3.09, 1.99, 2.00, 0.78, 1.32, 2.25, 3.15, 3.85, 0.52, 0.99, 1.38, 1.75, 1.22, 1.75}. Using this data, make a histogram.
