Chapter 8: Sampling Method

Chapter 8: Sampling Method

1. Probability Sample

   • a sample selected from person in population that being studied
   • if all sample of a particular size are selected from any population, the sampling distribution of the sample mean is approximately a normal distribution
     • if the population follows a normal probability distribution, then for any sample size the sampling distribution of the sample mean will be normal
     • if the population distribution is symmetrical but not normal, shape of the distribution of the sample mean will emerge as normal with samples as small as 10
     • If a distribution that is skewed or has thick tails, it may require sample of 30 or more observe the normality feature

2. Sampling Distribution of A Sample Mean

   • is a probability distribution consisting of all possible sample means