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Warm Up

Warm Up. Develop your own Stem and Leaf Plot with the following temperatures for June. . 77 80 82 68 65 59 61 57 50 62 61 70 69 64 67 70 62 65 65 73 76 87 80 82 83 79 79 71 80 77. Warm Up. Answer:. Lesson 5: Frequency. Frequency is how often something occurs.

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Warm Up

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  1. Warm Up Develop your own Stem and Leaf Plot with the following temperatures for June. 77 80 82 68 65 59 6157 50 62 61 70 69 6467 70 62 65 65 73 7687 80 82 83 79 79 7180 77

  2. Warm Up Answer:

  3. Lesson 5: Frequency • Frequency is how often something occurs. • Example: Sam played football on… • Saturday morning • Saturday afternoon • Sunday afternoon • The frequency is: http://www.mathsisfun.com/data/frequency-distribution-grouped.html

  4. Categorical Frequency Distribution By counting frequencies we can make a frequency distribution table A categorical frequency distribution is used for data that can be placed into specific categories.

  5. Creating a Categorical Frequency Distribution Step 1: Make a table with the following columns in order: class, tally, and frequency

  6. Creating a Categorical Frequency Distribution Step 2: Tally the data and place the results in the tally column.

  7. Creating a Categorical Frequency Distribution Step 3: Count the tallies and place the results in the frequency column.

  8. Example Categorical Frequency Distribution These are the favorite colors of fifteen 2nd graders. Red Yellow Green Red Blue Blue Red Red Green Red Green Yellow Red Blue Green Total=

  9. What about if the categories of data are numbers?

  10. Grouped Frequency Distribution A frequency distribution with classes that are more than one unit in width When the range of the data is large, the data must be grouped into classes 41 104 112 118 87 95 105 57 107 67 78 125 109 99 105 99 101 92

  11. Key Concept Class Limits: The values which determine the upper and lower limits of a class Lower Class Limit:Smallest data value that can be included in the class Upper Class Limits:Largest data value that can be included in the class

  12. Class Width The class width is the range of the class. Can be found by subtracting the lower class limit of one class from the lower class limit of the next class

  13. Rules For Grouped Data Rule #1: Choose the classes You will normally be told how many classes you need Rule #2: Choose Class Width ALWAYS round up to the next whole number Rule #3: Mutually Exclusive This means the class limits cannot overlap or be contained in more than one class.

  14. Rules For Grouped Data Rule #4: Continuous Even if there are no values in a class the class must be included in the frequency distribution. There should be no gaps in a frequency distribution. (with the exception of a class with zero frequency) Rule #5: Exhaustive There should be enough classes to accommodate all of the data Rule #6: Equal Width This avoids a distorted view of the data.

  15. Creating a Frequency Distribution Step 1: Determine the minimum and maximum values, and how many classes you need

  16. Creating a Frequency Distribution Step 2: Find the class width Class Width = __Range__ # of classes *ALWAYS round up to the next whole number

  17. Creating a Frequency Distribution Step 3: Write your minimum value as your lowest lower limit Class Limits Minimum value 2

  18. Creating a Frequency Distribution Step 4: Add the class width to your lower limit to find the next lower limit; WRITE BELOW NOT BESIDE! (do all lower limits first) Class Limits Ex: Class width = 9 2 11 20 29 Go until you have the amount of classes needed (in this case 4)

  19. Creating a Frequency Distribution Step 5: To find each upper limit, subtract one from the next lower limit Class Limits 2 - 10 11 - 19 20 - 28 29

  20. Creating a Frequency Distribution Step 6: To find last upper limit, add class width to the 2nd to last upper limit Class Limits 2 - 10 11 - 19 20 - 28 29 - 37

  21. Frequency Distributions 102 124 108 86 103 82 71 104 112 118 87 95 103 116 85 122 87 100 105 97 107 67 78 125 109 99 105 99 101 92 Minutes Spent on the Phone Make a frequency distribution table with five classes. Minimum value = Maximum value = 67 125

  22. Steps to Construct a Frequency Distribution 1. Choose the number of classes For this problem use 5 2. Calculate the Class Width Find the range = maximum value – minimum. Then divide this by the number of classes. Finally, round up to the next whole number. (125 - 67) / 5 = 11.6 Round up to 12 3. Determine All Class Limits The lower class limit is the lowest data value that belongs in a class and the upper class limit is the highest. Use the minimum value as the lower class limit in the first class. (67) 4. Mark a tally | in appropriate class for each data value. After all data values are tallied, count the tallies in each class for the class frequencies.

  23. Construct a Frequency Distribution Table Class Limits Tally f Total=30 Minimum = 67, Maximum = 125 Number of classes = 5 Class width = 12 3 5 8 9 5 78 90 102 114 126 67 79 91 103 115 Do all lower class limits first.

  24. Try One On Your Own After conducting a survey of 30 of your classmates, you are left with the following set of data on how many days off each employee has taken this year: Construct a Frequency Table. Assume you want to divide the data into 5 different classes. 7, 8, 9, 4, 10, 36, 19, 9, 26, 5, 11, 6, 2, 9, 10, 8, 16, 29, 7, 9, 8, 25, 4, 27, 8, 7, 6, 10, 34, 8

  25. Answer Total: 30

  26. Homework Frequency Table Worksheet

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