Sampling Distribution

Generate Samples: Now, let’s sample 1000 times, every time we draw a sample of size 10, and compute the mean and SD for each sample.

means = replicate(1000,mean(rnorm(10,mean=5,sd=3)))
sds = replicate(1000,sd(rnorm(10,mean=5,sd=3)))

Notice the difference between the rep() and replicate() functions in R


Limit Laws : Rules of Thumb -

For most distributions, n > 30  will give a sampling distribution that is nearly normal
For fairly symmetric distributions, n > 15
For normal population distributions, the sampling distribution of the mean is always normally distributed

Confidence Intervals A point estimate is a single number, a confidence interval provides additional information about the variability of the estimate