2. Warm Up Develop your own Stem and Leaf Plot with the following temperatures for June. 7780826865 59 61 5750 62 61 70 69 64 67 70 62 65 65 73 76 87 80 82 83 79 79 71 80 77

3. Warm Up Answer: 50 7 9 61 1 2 2 4 5 5 5 7 8 9 70 0 1 3 6 7 7 9 9 80 0 0 2 2 3 7

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

5. 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. Categorical Frequency Distribution

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

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

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

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

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

11. 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 Grouped Frequency Distribution 41104112118 87 95 105 57107 67 78 125 109 99105 99101 92

12. Key Concept

13. 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 Class Width

14. 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. Rules For Grouped Data

15. 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. Rules For Grouped Data

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

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

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

19. 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 2 Ex: Class width = 9 11 20 29 Go until you have the amount of classes needed (in this case 4) Creating a Frequency Distribution

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

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

22. Frequency Distributions 102124108 86103 82 71104112118 87 95 103116 85122 87 100 105 97107 67 78 125 109 99105 99101 92 Make a frequency distribution table with five classes. Minutes Spent on the Phone Minimum value = Maximum value = 67 125

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

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

25. 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. Try One On Your Own 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

26. Answer Class LimitsTallyFrequency 2-814 9-158 16-222 23-294 30-362 Total: 30

27. Frequency Table Worksheet Homework