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 * Aim:** How do we use measures of dispersion for grouped data?

At the end of the lesson, you will be able to... 1. explain what is meant by grouped data, quartiles and inter quartile range 2. calculate quartiles and interquartile range, for both samples and populations, manually and using the graphing caculator 3. contruct and interpret box-and-whisker plots 4. compute the standard deviation for grouped data of sample and populations (we did this in the last lesson) 5. apply measures of dispersion in real-world situations 6. find the missing value in a data table given a measure of central tendency and the standard deviation

Before you watch these videos, write down the following questions in your notebook. Answer them as you watch the videos.
 * 1) What are the 5 values you need before you can create a box-and-whisker plot?
 * 2) Q2 is called the median. What is a way to find a median with a list of data?
 * 3) Q1 is called the first quartile. How do we determine the first quartile value?
 * 4) Q3 is called the third quartile. How do we determine the third quartile value?
 * 5) What does it mean if the distance is short between two points on a box-and-whisker plot? What does it mean if the distance between the two points is large?

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 * This video shows the steps how to create a box-and-whisker plot by hand**

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 * This video shows how to compare tow sets of data when graphed on box-and-whisker plots**

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 * This video shows how to use the graphing calculator to graph a box-and-whisker plot. Copy down the steps into your notes for future reference**

25, 12, 20, 18, 35, 25, 40, 35, 27, 30, 60, 22, 36, 20, 18, 27, 35, 42, 35, 55, 27, 30, 15, 22, 10, 35, 27, 15, 57, 18, 25, 45, 24, 27, 25
 * Classwork:** The following list show the length of time, in minutes, for each of 35 employees to commute to work

a. List the values of the five pieces of data you need to creat a box-and-whisker plot. b. Draw a box-and-whisker plot by hand c. Check your work on the graphing calculator d. Use the graphing calculator to answer the following: What is the minimum value, the maximum value, the median, the mean, the first quartile, and the third quartile?


 * Homework:** 2 - 20 even. use your graphing calculator as much as possible to answer these.

[|Box_n_Whisker.JPG]


 * Answers:**

[|A-box_n_whisker.JPG]


 * Journal entry:** The 5 numbers in the set {3, 4, 7, x, y} have a mean of 5 and a standard deviation of 2. If y>x, what is the value of x and y? Explain fully.