It is easy to see the frequency of each group number from the histogram. Write down the frequencies of all groups first, and then arrange these frequencies in order from big to small or from small to big.

If the number of these numbers is singular, then the middle number is the median of these data; If these numbers are even numbers, then the average of the middle two numbers is the median of this set of data.

Extended data

Describing a bar chart has three elements: number of groups, group width and group limit.

1, number of groups

Divide the data into several groups, and the guiding experience is to divide the data into 5~ 10 groups.

2. Group width

Generally speaking, the width of each group is the same. The selection of group number and group width is not independent. An empirical rule is: approximate group width = (maximum-minimum)/number of groups, then determine the initial approximate group width according to rounding, and then adjust it according to the data situation.

3. Group restrictions

It is divided into a group lower limit (the smallest data that may enter the group) and a group upper limit (the largest data that may enter the group), and a data can only be within one group limit. When drawing a bar graph, there are gaps between different groups; When plotting histograms, there are no gaps between different groups.

Bar chart is the most commonly used graph in statistical chart data analysis. The main features are:

1, which can make people see the size of each data at a glance.

It is easy to compare the differences between the data.