Sampling Methods

Testing a drop of blood to determine blood group, Quality control check of few products in factory, Tasting a spoonful of food to check salt

Sample inquiry involves collecting information from selected units, not all units. Census survey and checking all students' marks are population inquiries.

True

This is the fundamental principle of simple random sampling - every unit in the population has an equal probability of being selected for the sample.

Should represent the population, Should be randomly selected, Should be selected under identical conditions, Should have independent selection of units

An ideal sample should be representative, randomly selected, chosen under similar conditions, and have independent unit selection. It doesn't need all population units.