Bad sampling techniques often produce worthless data. This section introduces or reinforces many important definitions. Listeners calling in to respond to a question asked by a talk show host. Two variables are confounded when their effects on a response variable cannot be distinguished from one another. More of the group now have favorable opinions about Herkimer.
Purpose is to determine if the propaganda changed attitudes.
But, during the reading period, Herkimer makes headlines by donating a good amount of his personal fortune to a worthwhile charity. The reading of propaganda and the general knowledge of the charity donation are confounding variables. A list of sampling units. The method used to choose the sample. Sample is biased if it systematically favors certain outcomes.