1. Objective: to make and interpret frequency tables and histograms

2. Frequency types  Frequency: the rate at which something occurs or is repeated over a particular period of time or in a given sample. 5,8,2,9,3,8,2,5  Frequency of an interval: the number of a data values in that interval  Frequency table: groups a set of data values into intervals and shows the frequency for each interval

3. Math background (histograms)  A histogram is a special type of bar graph. The histogram is a summary graph showing a count of data points that fall into intervals of the range of a set of data values. Frequency and histograms correlate to one another. By providing a snapshot of the distribution of the data throughout the set, histograms summarize a set of data. In simpler words a histogram is a graph that can display data from a frequency table. In a histogram each interval has singular bar.

4. Examples HoursFrequency 0-5 6-11 12-17 18-23 65316531

5. If the bars are roughly the same height the histogram is uniform If a vertical line can divide the histogram into two parts that are close to mirror images than the histogram is symmetric If the histogram has one peak that is not in the center, the histogram is skewed

6. The number of text messages sent on one day by different students are shown below. What is a cumulative frequency table that represents the data? 17, 3, 1, 30, 11, 7, 1, 5, 2, 39, 22, 13, 2, 0, 21, 1, 49, 41, 27, 2, 0 Number of text messages FrequencyCumulative frequency 0-911 10-19314 20-29317 30-39219 40-49221

7. # of text message FrequencyCumulative frequency 0-911 10-19314 20-29317 30-39219 40-49221 1.Divide the data into intervals. The minimum is 0 and the max is 49. you can divide the data into 5 intervals 2.Write the intervals in the first column of each interval in the second column 3.For the third column, add the frequency of each interval to the frequencies of all the previous intervals

8. Try it!  What is a cumulative frequency table that represents the data below? 12, 13, 15, 1, 5, 7, 10, 9, 2, 2, 7, 11, 2, 1, 0, 15