1. Cautions and Biases AP Stats 10-17

2. Biased—if some characteristic of the pop. is underrepresented or overrepresented ***Bias is in the method, not the sample • Nonresponse—when an individual chosen for a sample can’t be contacted or does not cooperate

3. Voluntary response bias—ppl call in—those who care call, those who don’t care don’t call and will be underrepresented • Convenience sample—select only those easy to include (best friends, ppl in 4th period) • Judgment sample—use your judgment (or an expert’s) to choose what you think is a representative sample

4. Questionnaire bias—results from HOW you ask the questions