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Agenda

Learn about how outliers affect mean and median, choose the correct measure of center for summaries, and define data distribution with words.

candaceyoung
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Agenda

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  1. Agenda • Ixl/group time • Central Tendency day 2 • CW • Variation day 1 • CW

  2. Review Question Find the mean and median of each data set. a. 1, 2, 3, 4, 5 b.1, 2, 3, 4, 5, 100000 What effect does an outlier have on a data set’s mean? Big impact What effect does an outlier have on a data set’s median? Little impact

  3. 3-2 Measures of Center Day 3

  4. Discussion Company A’s mean salary is $55,000. Company B’s mean salary is $224,000. Who do you want to work for? Is it possible to work for Company B and make less money than for Company A? How?

  5. Discussion How does the outlier affect the mean? (show results) How does the outlier affect the median? (show results) Which measure of center best describes the salaries of each company? Why?

  6. Discussion How do you know when to use the mean or the median? *Use the mean when the data is “close together” *Use the median when you have an outlier

  7. Discussion Why is it important to know the effects of an outlier? People use it to mislead us Can someone give an example where this could be used to someone’s advantage?

  8. Today’s Objective You will be able tochoose the correct measure of center to summarize a data set.

  9. You Try! You will work together to come up with thorough solutions to the questions in your books. The solutions will include calculations and sentences.

  10. You Try! You will be working together in groups. You must work together in order to be successful. The ability to work with others is one of the most desirable skills that employers want. You will have to learn how to get along with people at work that you do not like. Today is a good time to practice this skill.

  11. You Try! In class assignment

  12. What did we learn today? Tochoose the correct measure of center to summarize a data set

  13. Review Question What do the mean and median summarize? The center of a data set. Today we are going to talk about a statistic that will summarize a different aspect of a data set.

  14. 3-3 Measures of VariationDay 1

  15. Discussion We know to use the mean when the data is close together. What does close together mean? In statistics, the way data is spread out is called distribution. This can easily been seen on a graph.

  16. Discussion Using your own words, describe the distribution of each data set.

  17. Discussion In statistics, we use values to describe how data is distributed (spread out). These values are called variation. Today we will just use words to describe how the data is distributed. In the days to come, we will learn these values of variation.

  18. Discussion Class Grades: 62, 65, 94, 95, 95, 96 The average grade is 85%. Does the average tell the entire story? The class grades has a distribution that is close together with two outliers. Does the distribution summarize the data better?

  19. Discussion The mean and median tell you about the middle of the data set and the variation explains how the data is spread out. Both statistics (measures of center and variation) are valuable because they help to summarize the data.

  20. Today’s Objective You will be able todefine the distribution of a data set using words.

  21. Definitions Variation – value used to describe the distribution of the data What does distribution mean? How the data is spread out What does the mean and median describe? Center of the data Notice how these two values are different.

  22. Definitions Today we are just going to use words to describe the distribution of the data set. Here are the words that we are going to use: Normal - close together Normal w/ an outlier - close together w/ an outlier Random - spread out

  23. Example 1: Class Grades Put 1 finger up if you think the distribution is normal, 2 if you think it’s random, and 3 if you think it’s normal with outliers. Period 1: 58, 62, 85, 88, 90, 93, 93, 95, 97, 98 Period 2: 78, 80, 80, 81, 83, 84, 84, 86, 88, 90 Period 3: 25, 40, 55, 70, 72, 74, 80, 98, 98, 99

  24. Example 2 Make up a data set (10 data points) that represents ages of teachers. Make the distribution normal with an outlier.

  25. You Try! In-class Assignment

  26. What did we learn today? Todefine the distribution of a data set using words

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