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 * Aim:** How do we use measures of dispersion: range, variance, and standard deviation?

At the end of the lesson, you will be able to... 1. define range, absolute deviation, variance, and standard deviation 2. compare and contrast the meaning of sample and population 3. use a graphingcalculator to calculate range, variance, and standard deviation for both samples and populations 4. apply measure of dispersion to real-world problems 5. interpret meaning of measures of dispersion in real-world situations

Before you watch the next two videos, write down the following questions in your notebook. Answer them as you watch the video.
 * 1) What is a population?
 * 2) What is a sample?
 * 3) What does dispersion mean?
 * 4) How does dispersion differ from measures of central tendency?
 * 5) What are the ways to measure dispersion?
 * 6) What is range? How is range calculated?
 * 7) What is variance? How is variance calculated?
 * 8) What does it mean if a variance is small? Large?
 * 9) What is standard deviation? How is a standard deviation calculated?

media type="youtube" key="E4HAYd0QnRc" width="425" height="350"
 * This video will tell you how to find range, variance, and standard deviation:**

media type="youtube" key="_x-XWDEIhfE" width="425" height="350"
 * Here is a video that organizes the data**

media type="youtube" key="5kz16kbOTG0" width="425" height="350"
 * This video demonstrates how to use the graphing calculator to figure out range, standard deviations and variances. Before you watch this video, copy down the following questions and answer them as you watch the video:**
 * 1) Write down the steps we use to find sample standard deviation and population standard deviation.
 * 2) What symbol is used for sample standard deviation? What symbol is used for population standard deviation?
 * 3) Using the graphing calculator how do we find the sample variance? How do we find the population deviation?


 * Classwork:** Answer the following. Be sure to use your graphing calculator to solve the problem.

[|Classwork p. 49.doc]


 * Homework:** 3-21 odd

[|variance_sd.JPG]

[|variance_sd2.JPG]


 * Answers:**

[|A-variance_sd.JPG]


 * Journal entry:** The mean for a math test and for a science test were each 80. The standard deviation of the math test was three and of the science test was 5. If Beverly scored 87 on each test, in which class did she do better when compared to her classmates? Explain your answer.