Unformatted text preview: know who is receiving which treatment observational studies : there’s no choice in regard to who goes into the treatment and control groups. regression line : best-fitting straight line that minimizes the sum of the squares of differences between observed values and the values predicted by the line. census : a complete enumeraiton of an entire population stratified random sample : population is divided into groups called strata and random samples of person from all strata are chosen. systematic sample : people selected using a system. ex. a person chosen for every five people pass by. convenience sample : based on choosing ind. who are easy to reach, are also suspect. ex. interviews at shopping malls tend to produce data highly unrepresentative of teh entire population often leading to undercoverage bias....
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- Spring '08
- Discrete probability distribution, ind., continuous random variable, discrete random variable