Block 46 Module 1

1. Measures of Central Tendency Block 46 Module 1

2. Welcome & Overview • Examine Next Generation Sunshine State Benchmarks related to Measures of Central Tendency • Administer Pretest • Introduce the module objectives • Developmental Activities: Measures of Central Tendency – Mean, Mode, Median Vocabulary development, problem solving, technology, error analysis/misconceptions • Review content: Journal entry

3. Next Generation Sunshine state Standards • MA.6.S.6.1: Determine the measures of central tendency (mean, median, mode) for a given set of data. • MA.6.S.6.2: Select and analyze the measures of central tendency to represent, describe, analyze, and/or summarize a data set for the purposes of answering questions appropriately • MA.7.S.6.1: Evaluate the reasonableness of a sample to determine the appropriateness of generalizations made about the population. • MA.8.S.3.2: Determine and describe how changes in data values impact measures of central tendency.

4. Objectives • Participants will: • Review the vocabulary related to measures of central tendency (MA.6.S.6.1) • Determine the measures of central tendency (mean, median, mode) for a given set of data. (MA.6.S.6.1) • Identify problem solving strategies that may be used to develop understanding and familiarity with measures of central tendency. (MA.6.S.6.2) • Explore how changes in data values and extreme values affect measures of central tendency. (MA.7.S.6.1; MA.8.S.3.2) • Explore the use of technology and other instructional strategies that may be used to facilitate student understanding of measures of central tendency. (MA.6.S.6.2) • Develop the ability to communicate mathematically through journal writing and problem solving. (MA.6.S.6.2)

5. ?Measures of Central Tendency? Brainstorming • What are measures of central tendency? • How are they used in everyday situations?

6. Measure of central tendency are used to describe the typical member of a population. • Depending on the type of data, typical could have a variety of “best” meanings. • Real life examples: • Most children in the 8th grade are 13 yrs old. • The median annual family income is $39,600 • Ft. Lauderdale’s average rainfall for the month of July is 6.6 inches.

7. 3 Measures of Central Tendency • Mean – the arithmetic average. This is used for continuous data. • Median – a value that splits the data into two halves, that is, one half of the data is smaller than that number, the other half larger. May be used for continuous or ordinal data. • Mode – this is the category that has the most data. As the description implies it is used for categorical data.

8. Developing Vocabulary Power Activity Describe and complete an activity that may be used to build student vocabulary power. Terms: central tendency, mean, median, mode, variability, range, set of data, frequency table, numerical data, categorical data, outliers, line plot, circle graph, continuous data, categorical data, common, middle, most often Access the eglossary@glencoe.com

9. Using manipulative materials “Manipulating the physical model not only helps [children] understand the formula but also promotes retention.” “Simply being able to state the algorithm for finding these statistics is not enough. To support the development of data sense, each of these should be developed meaningfully through concrete activities before introducing computation. (Reys, et. al. 2009; p. 395)

10. Models for finding the median of an odd/even amount of data in a given set Find the median of 2, 3, 4, 2, 6. Participants will use a strip of grid paper that has exactly as many boxes as data values. Have them place each ordered data value into a box. Fold the strip in half. The median is the fold.

11. Using Manipulative materials Interlocking cubes • Arrange interlocking/Unifix cubes together in lengths of 3, 6, 6, and 9. • Describe how you can use the cubes to find the mean, mode, and median. • Suppose you introduce another length of 10 cubes. Is there any change in i) the mean, ii) the median, iii) the mode?

12. Finding the mean lengths: Using adding machine tape • Activity: Return test scores to students on pieces of adding machine tape. The length of each strip is determined by the score (88 cm, and 64 cm). Tape the 2 strips of paper together (add). Write out the addition part on the back - 88, 8… Fold this in half (divide by 2). • Try doing it with 3 pieces of strips. Does it work? Explain.

13. Visualizing the Mode • Category 4 has the highest bar. • Category 4 is the mode. • The mode is the class, not the frequency.

14. Mean Median & Mode Purpose: Reinforce concepts through songs. Click in the link http://www.youtube.com/watch?v=uydzT_WiRz4 • Would you use this tool in the classroom? Why/why not? Explain.

15. Using poems, rhymes & Mnemonics Cheers: Mean, Median, and Mode Mean (Say in really mean voice and face throughout!)Add all the numbers (Have hand go from waist to neck in increments.)And Divide! (Have same hand slice across the neck!) Median …MiddleOrder numbers least to greatest (motion hand left to right)Find the middle. (move both hands to middle and clap) When I say mode you say MostMode….MostMode….Most!Mode is the number that appears most oftenMode…Most oftenMode…Most often!

16. Understanding The Mean • The mean is located between the extreme values. • The mean is influenced by values other than the mean. • The mean does not necessarily equal one of the values that was summed. • The mean can be a fraction. • When you calculate the mean, a value of 0, if it appears, must be taken into account. • The mean value is representative of the values that were averaged.

17. Calculating the Mean (Arithmetic Average) • To find the mean: add all of the values, then divide by the number of values. • A student’s score on 4 math tests are: 8, 5, 9, 6. Calculate the mean score. • Sum of all values 8 + 5 + 9 + 6 = 28 • Number of values = 4 • Mean = 28 ÷4 = 7 Mean score on the math test is 7 Check! 7 8, 5, 9, and 6 or 5, 6, 8, 9

18. The Median • The median is a number chosen so that half of the values in the data set are smaller than that number, and the other half are larger. • To find the median • List the numbers in ascending order • If there is a number in the middle (odd number of values) that is the median • If there is not a middle number (even number of values) take the two in the middle, their average is the median

19. Finding the Median • List values in order of size 5, 6, 8, 9 6 8 • Find the average of the selected values. (6 + 8) ÷ 2 = 7 Median score on the math test is 7 Check! 7 8, 5, 9, and 6 or 5, 6, 8, 9 • To find the median: list all of the values, in order of size. Select middle value(s) • A student’s score on 4 math tests are: 8, 5, 9, 6. Calculate the median score. M E D I A N

20. Group Activity Finding Mean, Median and Mode for data sets • Figure out the mean, median, mode, range, and outlier using a group/card activity Discuss the various measures. • Materials: 4 sets of activity cards (Nine 4 x 4 Index cards 1, 5, 6, 7, 8, 9, 10, 11, 12, 18) use either 1 or 18 as an outlier; calculators.

21. The Mode • The mode is simply the category or value which occurs the most in a data set. • If a category has more than the others, it is a mode. • Generally speaking we do not consider more than two modes in a data set. (i.e. Bi-modal) • No clear guideline exists for deciding how many more entries a category must have than the others to constitute a mode.

22. outlier effects on measures of central tendency • Give nine different students a card and have them come to the front of the room and hold their card facing the rest of the class. Give the remaining seated students a calculator.Follow directions on activity sheet. Discuss how the outlier affects the measures of central tendency.

23. Problem Solving Using different Strategies! Andy’s results on three tests are: 68, 78, and 88. 1. Find the mean and median score. 2. Explain why the mode is of little value. 3. What score would be needed on the next test to get an average of 81. 4. Describe two different ways you could determine this score.

24. Investigatingdescriptive statistics • Using technology

25. What Does It Mean to Understand the Mean? Plop It! • Participants will experiment with the concepts of mean, median, and mode by using a bar graph. • Participants will change parameters and discover patterns related to mean and median. They can choose their own focus of measure, their own quantity, and their own units. URL: www.shodor.org/interactivate/activities/plot/what.hmtl

26. Using Spreadsheets MA.8.S.3.2: Determine and describe how changes in data values impact measures of central tendency. • Purpose: use technology to calculate mean, mode, and median of a set of data. • Task: Make a spreadsheet for a given data set and find the measures of central tendency. (See slide 26 for data.) • Open a new spreadsheet. Create four columns labeled DATA, MEAN, MEDIAN, and MODE. • Enter each allowance amount in the DATA column. • In cell B2, enter =Average(A2:A11). In cell C2, enter =Median(A2:A11). In cell D2, enter =Mode(A2:A11). Each of these will find the mean, mode and median of the data set. • Analyze the results.

27. Mrs. Jensen’s 7th grade class was surveyed about how much allowance each student receives each week. The results are shown in the table. Use this information to make a spreadsheet for the data, and find the mean, median, and mode. Analyze the results. • What data value is an extreme for the set? Explain your reasoning. • Describe how the measures of central tendency would change if the extreme value was not included in the data set.

28. changes in data values impact on measures of central tendency • Example: Mrs. Donohue has told her students that she will remove the lowest exam score for each student at the end of the grading period. Sara received grades of 43, 78, 84, 85, 88, 78, and 90 on her exams. What will be the different between the mean, median, and mode of her original grades and the mean, median, and mode of her five grades after Mrs. Donohue removes one grade?

29. Communicating Mathematics Ideas Measures Central Tendency Quartile Mode Range Mean Median

30. Block 47 Module 2 Research into Practice & Constructing Appropriate Data displays

31. Objectives • Examine student misconceptions in statistical thinking. • Use researched information on statistical thinking to create activities geared at helping students develop better understanding of averages. • Connect Math and Language Arts by providing activities for students to develop their vocabulary skills while simultaneously developing conceptual understandings. • Construct and analyze histograms, stem-and-leaf plots, and circle graphs. • Make conjectures about possible relationships from data sets. • Identify teacher-specific instructional tools and methods for graphically displaying data. • Explore web-based educational resources designed to reinforce learning of graphical displays and measures of central tendency.

32. Benchmarks • MA.6.S.6.2: Select and analyze the measures of central tendency or variability to represent, describe, analyze, and/or summarize a data set for the purposes of answering questions appropriately • MA.7.S.6.2: Construct and analyze histograms, stem-and-leaf plots, and circle graphs. • MA.8.S.3.2: Determine and describe how changes in data values impact measures of central tendency.

33. Misconceptions “Many middle graders are able to calculate averages but their understanding of the concept of average is shallow.” (Reys, et al., 2009). Participants will identify misconceptions students might have about statistics.

34. Connecting Research and Practice Purpose: to review measures of central tendency, and provide an opportunity for participants to use research findings to inform their instructional practices. • Task: Participants will read 1 research article on Measures of Central Tendency. • Participants will summarize the article and discuss the main findings as they apply to the teaching and learning of Measures of Central Tendency.

35. Difficulties in interpretingthe Mean “Akira read from a book on Monday, Tuesday and Wednesday. He read an average of 10 pages per day. Circle whether each of the following is possible or not possible.”

36. Outcome: • Less than 40% answered all 4 choices correctly. “Many middle graders are able to calculate averages but of understanding of the concept of average is shallow.” (Reys, et al., 2009, p. 396). Remediation Activity Work with a partner to develop an activity to help students better understand the concept of average. Present your activity to the class with a rationale for selecting this activity.

37. Misconception about the median • Problems involving finding the median Problem: When finding the median of an even-numbered set of data, some students use the mean the data instead of the mean of the two middle numbers. Describe an activity that may be used to help students overcome this problem.

38. Word Frame: Differences & Similarities

39. Focus question/Activity • How are statistical displays helpful to us in our everyday lives? Make a list of the different types of graphs that you know. Select one of the graphs, and write about a situation in which you will use that graph to display data.

40. MISLEADING GRAPHS Participants compare two Bar graphs with the same data, and discuss why one may be misleading.

41. Error Analysis • To look at a student’s sleeping pattern a student made a Line Plot of the number of hours he slept each night for one week. Describe the student’s error and tell which display he should have made.

42. Using TechnologyConstruct & analyze histograms and circle graphs Group Activity • Assign groups of no more than 4per group. Participants use the computer to get a feel for the technology and discuss the usability and benefits of including such tools in the 6-8 math curriculum. • Circle grapher, and histogram tool http://illuminations.nctm.org/ActivityDetail.aspx?

43. Choosing an appropriate displayWhy Me! Which graph would you use to compare the number of red folders sold by two stores in one week?”

44. Converting a Bar graphinto a Circle graph • Instruction: Copy a Bar graph. Write a label on each bar. Cut our each bar from the graph. Tape the ends together (no overlaps) to form a circle. • Place the circle on a sheet of paper. Trace the circle. Mark where each bar begins and ends around the circle. • Mark the center of the traced circle. Draw in a radius from each of the lines marked on the circle. • Color the sections of the circle. Label each section, and title your graph.

45. Data Analysis & Measures of Central tendency

46. ACT IT OUT: STEM AND LEAF PLOTS • Problem Solving Strategy: Act it out Given the data set: 7, 51, 25, 47, 42, 55, 50, 26, 44, 55, 26, 33, 39, participants will: Copy the numbers unto individual index card. Sort the cards into piles based on place value. (Stem value) Note what they have in common Cut one of the stem, place it on a sheet of paper or the table. Cut the remaining leaves with this stem. Add the leaves to the leaf section of the plot. Repeat for each of the piles. Discuss the plot by examining the lowest and highest scores, the lengths of each leaf, gaps, tapers, and the median and modal values.

47. STEM and LEAF Plot Activity: • Create the plot from the information presented below. An example of a stem-and-leaf plot for the data set (34, 30, 38, 42, 67, 68, 68, 56, 54, 34, 82, and 85) is as follows: Legend: 3|234 • Discuss what is the • median of the data set? • mode of the data set?

48. Review Exercise • What does the data represent? • What type of central tendency would you use to represent it? Why? Include each of the measures in your justification. • Sketch the type of graph you would make to represent the data set. • How can the data representation influence conclusions?

49. Thank you for Completing Module 46.2

50. Block 46 Module 3 L Graphs & Measures of Variation