Hobbies And Interests
Instructions
Count the total number of observations in your data set. Counting is best accomplished by ordering your data into a single vertical column and counting the number of lines. In this example there are 20 lines of data.
12
12
7
7
11
8
8
11
11
10
10
10
10
9
11
11
8
8
12
12
Order the values from highest to the lowest value. In this example:
7
7
8
8
8
8
9
10
10
10
10
11
11
11
11
11
12
12
12
12
Calculate the range of your data set by subtracting the highest value from the lowest value.
For this example:
13-7 = 6
Calculate the number interval widths by dividing the range by the number of intervals, in this example, 2.
6/2=3
Arrange the data into the appropriate intervals.
In this example interval one will contain values between 7 and 9 and interval two will contain values between 10 and 12:
Interval one: 7, 7, 8, 8, 8, 8, 9
Interval two: 10, 10, 10, 10, 11, 11, 11, 11, 11, 12, 12, 12, 12
Determine the appropriate base by counting the largest number of digits in the data set. In this example, all the numbers are single or two digits so a base ten is appropriate.
Construct your stem-and-leaf plot by separating the leaves and stems and counting the number of data points that fall into each group. In this example the stem of 0 contains the interval of numbers between 7 and 9 and the stem of 1 contains numbers between 10 and 12.
Arrange your data so the first column contains the number of observations in each interval, the second column contains the name of the stem and the third column contains the values in the leaves.
In this example:
7 0 7788889
13 1 0000111112222