an extraction step of analyzing data to be analyzed and extracting a subject whose appearance frequency in the data to be analyzed satisfies a predetermined condition among subjects detected in the data to be analyzed; and

an output step of outputting information regarding the extracted subject.

17-2. The data processing method described in 17,

in which the extraction step includes a person extraction step of analyzing moving image data to be analyzed and extracting a person whose appearance frequency in the moving image data to be analyzed satisfies a predetermined condition among persons detected in the moving image data to be analyzed, and

the output step includes outputting information regarding the extracted person.

17-3. The data processing method described in 17-2,

in which the moving image data to be analyzed includes a plurality of pieces of child data captured at a plurality of places different from each other, and

the person extraction step includes determining whether or not each person detected in the analyzed moving image data appears in each of the plurality of pieces of child data, and calculating an appearance frequency of each person detected in the analyzed moving image data based on a result of the determination.

17-4. The data processing method described in 17-2,

in which the moving image data to be analyzed includes moving image data captured at the same place over a predetermined time period, and