# STAT 101 Lecture Notes - Lecture 8: Simple Random Sample, 5,6,7,8, Convenience Sampling

## Document Summary

Population versus sample: the distinction between population and sample is basic to statistics. Sampling badly: a sample selected by taking the members of the population that are easiest to reach is called a convenience sample. Bias: the design of a sample is biased if it systematically favors certain outcomes, caution: people who take the trouble to respond to an open invitation are usually not representative of any clearly defined population. Voluntary response sample: a voluntary response sample consists of people who choose themselves by responding to a general appeal. Voluntary response samples show bias because people with strong opinions are most likely to respond. In practice, people use random numbers generated by a computer or calculator to (cid:272)hoose sa(cid:373)ples. If you do(cid:374)"t ha(cid:448)e te(cid:272)h(cid:374)ology ha(cid:374)dy, you can use a table of random digits. Choosing srs: a table of random digits is a long string of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 with these properties: