Module 4 Flashcards
inferential statistics
use a sample’s statistics to esitmate population statistics (parameters)
parameter is an idea more than something concrete that you can access
population parameteres
CAN’T ever access them, you can only conceive of them in your mind through inferential statistics
make inferences about everyone
estimating a population SD and mean
samples have SDs and means, we can use those samples drawn from a larger population
our best guess for the population mean is using the sample mean from that population
sampling error
different random samples from the same population produce different sample means - this is sampling error
sample means are UNBIASED because they are normally distributed
estimating a population standard deviation (standard error)
sample SD is biased and it underestimates the population SD
so we use this equation with (n-1) to account for
degrees of freedom
sampling distribution of the means
the mean of the distribution of the means
standard error of the mean
the standard deviation of the sampling distribution of means
central limit theorem
- the mean of the distribution of means is equal to the mean of the population
- a population has a standard deviation called the standard error - the standard error is always less than standard deviation as long as N > 1
- the sampling distribution is approxiamtely normal
- each sample has a different sampling distribution
- larger samples ivolve less sampling error