AP Stats unit 5

What happens as sample size increase

the spread decreases and the center becomes more accurate

central limit theorem

must be calculating sample means, samples must be taken independently of each other or n is less than 10% of the population, the population must be normally distributed or the sample size must be at least 30 if above conditions are met, the sampling distribution is approximatley normal, state mean and sd

Determining shape for difference of means

the clt must apply to both means

estimators

stats used to estimate unknown population parameters, biased if the mean is not equal to the mean of the population parameter. as sample size increases, the mean get closer to the true mean

sample variability

the natural tenedency for mean or proportion to differ across sample sizes even if they are taken from the same population, larger samples have less variability