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Frequency Tables and Histograms. Math 153 – Introduction to Statistical Methods. Objectives. Create a frequency table using raw data obtained from the Internet. Use Statdisk to create a histogram based on our frequency table. Use the TI calculator to confirm results.
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Frequency Tables and Histograms Math 153 – Introduction to Statistical Methods
Objectives • Create a frequency table using raw data obtained from the Internet. • Use Statdisk to create a histogram based on our frequency table. • Use the TI calculator to confirm results. • Understand the effect of the class width on the shape of a histogram.
Creating a Frequency Table • It is easier if you sort the data. Use the TI’s sort feature. • Determine the class width using the formula • Convention says to a minimum of five classes and a maximum of twenty classes. • Number of classes will affect the shape of the distribution.
Website Exercise Part 1 • Connect to the URL below and change the number of classes (called bins at the website). Email me what you notice about the change in the shape of the distribution. • Histogram Web Exercise • You will need to have Java enabled in your browser to view this web site.
Creating Graphs Using your TI • Enter the x values of your data into L1. • Select 2nd >> Stat Plot. • Turn plots “on” and then select the histogram option. • Finally, select ZOOM >> ZoomStat to create the best histogram for your data. • If you need further assistance, please go to the TI Tutorial.
Using Statdisk to create Histogram • Enter data in column 1 of the Statdisk data window. • From the menu bar, select DATA >> HISTOGRAM. • Under Plot Options, select USER DEFINED. • Enter your starting point and class width. • Hit the PLOT button. • If you need further assistance, go to your Statdisk tutorial.
Effect of Class Width • Number of classes is 5.*
Effect of Class Width • Number of classes is 2. • This is a very small data set. It’s sole purpose is to show the effect of class width on a histogram.
Effects of Outliers • Outliers are data points that are far away from the general data values. • Like their effect on the mean and standard deviation, they effect the shape of histogram as well.
Homework • Your next web assignment can be found at the Webquest link. Complete all questions using Microsoft Word and Statdisk. Email me your completed project.