NATS 1500 Lecture Notes - Lecture 11: Simple Random Sample, Confidence Interval, Sampling Frame
Document Summary
Margin of error getting slightly less or slightly more than the number expected. It reflects and takes into account the random variability you would get from sampling a different sample (from sample to sample) Approximately plus or minus two standard deviations. Will bounce around covering about 95% of the standard deviation missing about 5% of the value. The error that comes from randomness from sampling - but it doesn"t tell us about the randomness caused by other and maybe external sources, for example bias in the samples. Professor talks about the example of flipping a coin; your sample will have a variance because it"s nearly impossible for the coin to flip both heads and tales equally. Depends on the size of the sample, not the size of a population (india example) which resulted in the random variability. Simple random sample (srs) ha to give everyone in the population the same opportunity in getting in the sample.