MATH201 Lecture Notes - Lecture 10: Sampling Distribution, Standard Deviation
3 Aug 2016
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Document Summary
In previous work with probability distribution, we assumed that we knew the probability distributions associated with a range of values. With this knowledge, we are able to compute the mean, variance, and probabilities. However, in most practical applications, this information is not available. In most applications, the true mean and standard deviation are unknown quantities that need to be estimated. Average number of cavities per child in grade school. 1000 children from across the country were randomly selected and the number of cavities for each was determined. The inference is that the average number of cavities found in the sample generalizes to the population american grade-school children. This is how we use sampling to estimate values such as mean and standard deviation in a population. Parameter: a numerical descriptive measure of population: because it is based on the observations in the population, its value is almost always unknown.
