The arithmetic average describes the average trend of a set of data and is the quotient of the sum of all data divided by the number of data. When used in statistics, it should be noted that when there are extreme values, ambiguous data or different quality data, the arithmetic average can not be calculated.
According to the above definition, which of the following options is suitable for calculating arithmetic averages?
According to the statistics of a certain city, the average number of left-behind children in each district and county of the city, among which the districts and counties with a large number of migrant workers are unable to make accurate statistics, only the estimated data are provided.