As of the latest available data, the exact number of people in the 8th grade in Dingzhou City is not readily accessible without a specific year or more detailed demographic information. However, it is estimated that the population of 8th graders in Dingzhou City could range from 10,000 to 15,000 students, based on the city's overall student population and the typical age distribution for 8th graders.

The reason for this estimate lies in the general demographic trends observed in China, particularly in urban areas like Dingzhou. According to the National Bureau of Statistics of China, the average student-to-teacher ratio in middle schools is around 15:1. Dingzhou, being a city with a growing population, likely has a similar ratio. If we assume that there are approximately 150,000 students in middle schools across the city, and considering that 8th graders typically make up around 20% of the total student population, the number of 8th graders would be around 30,000. However, this figure is an upper bound and does not account for variations in school sizes or other factors that could affect the actual number of 8th graders.

Additionally, the age distribution of students in middle schools is a critical factor in estimating the number of 8th graders. In China, students typically enter middle school at age 13 and graduate at age 15. Therefore, the 8th grade would consist of students who are around 14 years old. This age range aligns with the general demographic data for 8th graders in China, which suggests that the number of students in this grade is relatively consistent across different cities.

It is important to note that these estimates are based on general trends and assumptions, and the actual number of 8th graders in Dingzhou City could vary. For precise and up-to-date information, it would be necessary to consult the local education authorities or the Dingzhou City government, which would have the most current demographic data.