Example 1 100 people participated in 7 activities. It is known that everyone only participates in one activity, and the number of participants in each activity is different. So, how many people can participate in the event with the fourth largest number of participants?

A.22 B.2 1 C.24 D.23

Analysis: Divide these seven activities into two groups, {1-4} and {5-7}. To make the fourth place score the most, {5-7} should be as few as possible, at least 1+2+3 = 6, and at most 100-6 = 94 {1-4}. 94 ÷ 4 = 23.5. At present, the number of people in the four activities is 25, 24, 23 and 22 respectively, and the maximum number of people in the fourth activity is 22.

When solving a problem, we can group the data according to the stem conditions, and discuss the discreteness of this group of data after grouping, so as to determine the extreme situation of different data combinations under given conditions. With the development of the proposition, there are some deformations in the topic of data analysis at this stage, which makes the data grouping more complicated, and the worst discreteness of single group data is no longer limited to simple arithmetic progression.