CONTRASTING SAMPLING METHODS PRE444 Sampling methods are important because they can affect the validity of the data. You NEVER want to used a biased sampling method! It’s like asking people eating cookies if they like cookies. It makes your survey or study a joke because your data is invalid. Sometimes the sampling method depends on what you’re trying to learn…

CONTRASTING SAMPLING METHODS PRE444 Telephone every 10 th person in the telephone book? Walk up to people on the street or in the mall? Ask 25 citizens who are 18-25, 26-40, 41-55, 56+? If you are on the city council and want to build a new library, city hall, or park, which sampling method would you choose?

CONTRASTING SAMPLING METHODS PRE444 Telephone every 10 th person in the telephone book? Walk up to people on the street or in the mall? Ask 25 citizens who are 18-25, 26-40, 41-55, 56+? All of these are unbiased methods but in this case the stratified random method might give you more useful information than asking people in the mall or every 10 th person in the telephone book. The method you use can make a difference!