| Flap 1 |
Flap 2 |
| Population | The group of individuals that we hope to learn about |
| Sample | A part of the population that we examine in hope to learn about the population |
| Sample survey | Questions that are given to a sample in hope of learning something about the entire population. EX: Polls |
| 4 types of Bias | 1) Relying on Voluntary response 2)undercoverage of the population 3) nonresponse bias 4) response bias |
| Randomization | The best defense against bias. Each individual is given a fair, random chance of being select |
| Matching | Force a sample to resemble specific attribute |
| Sample size | # of individual in a sample. |
| Census | A sample that consist of the entire population |
| Population parameter | EX: the mean income of all employed people in the country |
| Statistic, sample statistic | values calculated for sampled data |
| Representative | a sample is representative if the statistics computed from it accurately reflect the corresponding population parameters |
| Simple random sample | each set of (n) elements in the population has an equal chance of being selected |
| Sampling frame | Lists of individuals from the sample |
| Stratified random sample | population is divided into several strata, and random samples are drawn from each stratum. |
| Cluster sample | entire groups or clusters are chosen at random |
| Systematic sample | selecting individuals systematically from a sampling frame |
| Multistage sample | sampling schemes that combine several sampling methods |
| Voluntary response bias | individuals can choose on their own whether to participate in the sample. Sample base on voluntary response is always invalid. |
| Convenience sample | individuals who are conveniently available. Not representative because every individual is not equally convenient to sample |
| Nonresponse bias | large fraction of those sampled fail to respond. Those who do response are likely not to represent the entire sample |
| Response bias | The people tell lies because you asked a sensitive question. EX: Do you do drugs? |
| Sampling variability | tendency of randomly drawn samples to differ, one from another. |
| interviewer bias | the person you having conducting the interview makes the person hesitant to answer the questions |
| Reporting Bias | the individual tends to round when answering |
