1. Why is Statistics Important
Foundational Concepts

2. Consider This
Marketing cheeseheads to residents of Ashland & Bayfield counties (in 1990)
Need to know the mean age and percentage of males
Foundations I

3. How Should You Proceed?
Want to know the mean & percentage male for the entire population
Is this possible or reasonable?
The best we can do is look at a sample (i.e., a portion of the population)
How do we do that?
How are individuals selected?
How many individuals should be selected?
Foundations I

4. Complete the Class Exercise
Foundations I

5. Summary – Principles Statistics helps with these issues
We cannot “see” the entire population
i.e., we must sample to learn
Variability is everywhere
among individuals – Natural Variability
among summaries of samples – Sampling Variability
Conclusions are uncertain
because population is unknown and variability
Statistics helps with these issues
That is WHY you are here!!!
Foundations I

6. Summary – Goals of Statistics
Description / Summarization
Distill large amounts of data into a few informative numerical or graphical summaries
Inference
Make conclusions about the entire population from information gathered from the individuals in a sample
Foundations I