Chapter 19 – Diversity of Samples From the Same Population
We collect samples from a population, measure the variable, answer the question, determine how close
the answer from our sample is to the answer for the population.
We need to understand the dissimilarity we see in various samples from the same population. With
sample values we can make a good guess at what the population value is.
In random samples we may not see the exact probability of a certain event. This is because probability is
over the long run. There is a rule for sample proportions that applies for what to expect in possible
1) There exists a population who have a certain trait, gene, etc… or there is a repeatable
situation where there is a relative frequency probability
2) A random sample is selected from the population or the situation is repeated many times
3) The size of the sample/# of repetitions is large.
The rule for sample proportions is standard deviation = sqrt(true proportion x [1-true proportion/sample
There is also a rule for what to expect from sample means. Thi