1. Sampling Distributions
Section 9.1

2. Parameter A number that describes the population
A fixed number…but in practice it is not known

3. Statistic A number that describes a sample
Can change from sample to sample
Used to estimate an unknown parameter

4. Symbols  is the mean of a population x bar is the mean of a sample
p represents a population proportion
p hat represents a sample proportion

5. Sampling Variability
The value of a statistic varies in repeated random sampling

6. Sampling Distribution
The distribution of values taken by the statistic in all possible samples of the same size from the same population

7. Unbiased Statistic
A statistic is unbiased if the mean of the sampling distribution is equal to the true value of the parameter being estimated

8. Variability of a Statistic
Described by the spread of its sampling distribution
Large samples give smaller spread

9. As long as the population is much larger than the sample, the spread of the sampling distribution is approximately the same for any population size

10. Practice Problems pg. 489 #9.1-9.4 pg. 499 #9.8