The idea of stem-leaf diagram is to compare the numbers in the array according to the number of digits, take the numbers with basically the same size or little change as the trunk (stem), and list the numbers with large size change as branches (leaves) behind the trunk, so that you can clearly see the numbers behind each trunk. What is the specific number of each number? .

There are three columns in the stem-leaf diagram: the left column is the number system count, which is the value accumulated up (or down) to the center, and the number in the center (with brackets) indicates the number of the most array.

The middle column represents the stem, that is, the digits that have not changed much. On the right is the change bit in the array, and the number of changes in the array is listed one by one at regular intervals, just like a leaf pulled from a branch.

Extended data

Rotating the stem-leaf diagram counterclockwise by 90 degrees is actually a histogram, from which you can count the number of times and calculate the frequency or percentage of each data segment. So we can see whether the distribution is close to normal distribution or unimodal skewed distribution.

Its advantages are that the original data information is not lost from the statistical diagram, and all data information can be obtained from the stem and leaf diagram. The data in the stem leaf diagram can be recorded and added at any time, which is convenient for recording and representing.

The disadvantage is that the stem-leaf diagram is only convenient to represent the data with little difference before the unit, and the stem-leaf diagram is only convenient to record two groups of data. Although more than two data can be recorded, it is not as intuitive as two records? .

Baidu encyclopedia-stem leaf map