Reporting Frequency Frequency Tables Histograms.

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