Statistics are divided into qualitative data and quantitative data. Qualitative data includes categorical and ordinal data. Categorical data refers to non-numeric data that can only be assigned to a certain category, which is the result of classifying things and expressed in words; sequential data refers to non-numeric data that can be assigned to an ordered category. Quantitative data are data that represent specific numerical observations. ①Cities can be divided into megacities, large cities, medium cities and small cities according to the size of the city; ②Marital status: 1-unmarried, 2-married, 3-divorced, 4-widowed; ③The distance from place A to place B is 200 kilometers, 320 kilometers to C and 100 kilometers to D; ④ A hospital has a construction area of 50,000 square meters, 3,182 open beds and 687 clinicians.
Based on the above definition, ②④ are classified data.