The ideal data for stratified sampling:

Stratified Random Sampling The non-homogenous population is converted to homogenous groups/classes (strata); sample is drawn from each strata at random, in proportion to its size. Applicable for large non-homogeneous population. Gives a more representative sample than simple random sampling. None of the categories is under or over-represented. For example, In a population of 1000, a sample of 100 is to be drawn for Hemoglobin estimation; first convert non-homogenous population to homogenous strata (i.e. 700 males and 300 females), then draw 70 males and 30 females randomly respectively.