Biology 2244A/B Lecture Notes - Lecture 5: Sample Space, Random Variable

• School: Western University
• Department: Biology
• Course: Biology 2244A/B
• Professor: Ingrid L.Stefanovic

Document Summary

Random samples eliminate bias from the act of choosing a sample, but they can still be wrong because of the variability that results when we choose at random. Answers for statistical questions depends on variability and varies from sample to sample. Chance is used to choose simple random samples which is why the laws of probability govern the behaviour of sample statistics. Larger samples with smaller variability give better estimates of population parametrs. Chance behavior is unpredictable in the short run but has a regular and predictable pattern in the long run. The intuitive idea of probability is that with more trials, a pattern will emerge. We call a phenomenon random if individual outcomes are uncertain but there is nonetheless a regular distribution of outcomes in a large number of repetitions. The probability of any outcome of a random phenomenon is the proportion of times the outcome would occur in a very long series of repetitions.