 Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum            Session 3, Part C:
Relative and Cumulative Frequencies

In This Part: Relative Frequencies | Cumulative Frequencies
Relative Cumulative Frequencies

 As in Session 2, we can determine cumulative frequencies for intervals of data. For example, the number of responses that are less than 60 is the cumulative frequency of 60. (Note that "below 60" means "in the 50s and below.") If you begin with the stem and leaf plot for the 52 estimates of a minute, the 22 values in the lighter color are the estimates below 60: The corresponding 22 dots are shown in the dot version of this stem and leaf plot: And finally, the corresponding bars in the frequency histogram are shown in red: These three representations tell us that there are 22 estimates below 60. Problem C3

Complete this cumulative frequency table with the information you collected from the histograms above:   Interval Frequency Cumulative Frequency  30 to < 40 4 40 to < 50 1 50 to < 60 17 22 60 to < 70 18 70 to < 80 7 80 to < 90 4 90 to < 100 1    Interval Frequency Cumulative Frequency  30 to < 40 4 4 40 to < 50 1 5 50 to < 60 17 22 60 to < 70 18 40 70 to < 80 7 47 80 to < 90 4 51 90 to < 100 1 52  Problem C4 Use only the cumulative frequencies from the table to answer the questions below. As with Problem C1, first determine whether a question can be answered using only this table.

 a. How many responses are in the 70s and below? b. How many responses are 80 or higher? c. How many responses are in the 50s and below? d. How many responses are 60 or higher? e. How many responses are less than 100? f. How many responses are at least 40 but below 70? g. How many responses are 65 or greater? h. How many responses are less than 35? i. How many responses are equal to 60?   Session 3: Index | Notes | Solutions | Video