Stem and Leaf Plot A stemandleaf plot looks something like a bar chart. Each number in the data is broken down int a stem and a leaf. The stem of the number includes all, but the last digit. The leaf of the number will always be one digit. Look at the stem and leaf table below that was built from the following data: 40, 42, 45, 49, 51, 54, 57, 58, 60, 63, 66, 66
Key: 5  7 = 57


These diagrams should help you picture the meaning of stem and leaf. The first part of the number is the stem and the last digit is the leaf. 



This chart shows different numbers and inicates the stem and leaf for each number.
Key: 125  2 = 1252


Let's examine a stem and leaf plot:
The range of the 10 numbers shown is 105 to 135. The 10 numbers displayed above are: 105 110, 112, 113 120, 125, 125 130, 132, 135 The mean is the sum of the 10 numbers divide by 10. mean = (105+110+112+113+120+125+125+130+132+135)/10 =1207/10 = 120.7 The median is the middle number of the 10 numbers in order. Since there are 10 numbers we will have to find the average of the 5th and 6th numbers. median = (120 + 125)/2 =122.5 The mode is the number that occurs most often in a set of numbers. 125 is the only number that appears more than once. mode = 125 

A natural way to organize data is to arrange the data from least to
greatest. For example, the 30 weights: 185, 160, 235, 165, 125, 175, 185, 132, 168, 112, 170, 155, 105, 158, 120, 190, 140, 185, 125, 180, 145, 110, 155 135, 170, 113, 155, 175, 145, 130 are more easily comprehended in order: 105, 110, 112, 113, 120, 125, 125, 130, 132, 135, 140, 145, 145, 155, 155, 155, 158, 160, 165, 168, 170, 170, 175, 175, 180, 185, 185, 185, 190, 235. Note that each weight has been listed as many times as it occurs. This information can be visually presented with a stem and leaf plot. Remember that the leaf will always be one digit. The stems are listed on the left, and the corresponding leaves (if any) on the right. A stem and leaf plot for the above data is presented below.
range: 105 to 235 mean: 4598/30 = 153.2 median: (155+155)/2 = 155 (average of 15th and 16th numbers in set) modes: 155, 185 

Sometimes to enhance visual presentation of data, stems will be split (e.g., repeat each stem on the left, once for the digits 04, once for the digits 59). 