reporting frequency frequency tables histograms
TRANSCRIPT
Reporting Frequency
Frequency Tables Histograms
What is a Frequency Table?
• A Frequency table is a table that lists each item in a data set with the number of times it occurs.
Construct a Frequency Table (tally sheet)
Enter the data value into the 1st columnData Value Tally Frequency
0
1
2
3
4
5
6
7
8
9
10
7, 10, 10, 9, 8, 9, 7, 4, 3, 7, 10, 4, 8, 9, 6, 7, 10
Construct a Frequency Table (tally sheet)
Enter a tally for each entry.Data Value Tally Frequency
0
1
2
3
4
5
6
7
8
9
10
7, 10, 10, 9, 8, 9, 7, 4, 3, 7, 10, 4, 8, 9, 6, 7, 10
Construct a Frequency Table (tally sheet)
Count the tallies and put the total for each value in the frequency column
Data Value
Tally Frequency
0
1
2
3
4
5
6
7
8
9
10
12
14
4
23
Making a Line plot• • • x x• x x x• x x x x x• x x x x x x x
3 4 5 6 7 8 9 10
What is the range? 7
What is a Histogram?
• A histogram is a bar graph with no spaces between the bars. The height of each bar shows the frequency of data within that interval. The intervals of a histogram are of equal size and do not overlap.
Histogram
10
9
8
7
6
5
4
3
2
1
10-Jan 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-90 90-99
Fre
quen
cy
Test Scores
Class Test Scores
95 flashlights are tested until they fail. The table gives the times taken ( hours ) until failure.
Time to failure (hours)
0-19 20-29 30-39 40-44 45-49 50-59 60-89
Number of components
5 8 16 22 18 16 10
Find 2 or more things wrong with the histogram which represents the data in the table.
Histograms
Answer:
Time to failure (hours)
0-19 20-29 30-39 40-44 45-49 50-59 60-89
Number of components
5 8 16 22 18 16 10
• There is no title.
• There are no units on the x-axis.
Histograms
Time taken for 95 components to fail
Time to failure (Hours)
Histogram
• Histograms are used to show the frequency of data.
• Very similar to bar graphs, but use intervals on the X axis.
• Bars do touch.
• Histograms have a title.
• Histograms have two axes which are labeled.
Reporting Frequency
Frequency Tables Histograms