7/24/2019 ADJ COMP - Samples
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RELIABILITY OF SAMPLE ESTIMATES FOR POPULATION
How reliable or confidence is the mean and variance of sample
estimating the
population mean and variance can be determined based on sampling
distribution
theory and statistical hypothesis testing.
Sampling distribution theory states that the estimates for the
mean and
variance vary from sample to sample and have their own
population distributions.
Three distributions (Chi-square, t and F) used for quantifying
the reliability of
mean and variance estimates.
Based on these distributions, confidence interval can be
determined within
which the population mean and variance can be expected to fall
at any given
level of confidence or probability.
Statistical test using chi-square distribution is to check if
the sample varianceis a valid estimate for the population variance.
Statistical test using t distribution
is to check if the sample mean is a valid estimate for the
population mean.
Statistical test using F distribution is to check whether the
ratio of two variances
is statistically equal to 1.
