Statistics Titorial

1. Unit 1:
Introduction to
Statistics
TUTORIAL– POPULATIONS AND SAMPLES

2. Learning Target

You will be able to distinguish between a population and a sample.

3. Remember from the class
discussion…

A population is the complete collection of all measurements or data
that are being considered.

A sample is a sub-collection of members selected from a
population.

4. Populations and Samples

What is the main difference between the following scenarios?
1)
I am going to conduct a survey of every house on my block to see
what they think of their water quality.
2)
I am going to every fourth house on my block to ask them what they
think of their water quality.

5. Populations and Samples: Example
Identify the population and the sample in this situation:

A Gallup poll asked 1226 adults in the U.S. how often they exercised
each week.

6. Parameters and Statistics

A parameter is a numerical measurement describing some
characteristics of a population

A statistic is a numerical measurement describing some
characteristic of a sample.

7. Parameters and Statistics

What is the main difference between the following
scenarios?
1) There were 200 seniors that graduated from DLS last year. Of
those 200, 100% of them went on to some form of college.
2) Based on a sample of 200 Michigan seniors who graduated last
year, 48% of them went on to some form of college.

8. Parameters and Statistics: Example

Which is a parameter and which is a statistic and why?
1) A survey of 877 corporate executives found that 45% of them
would not hire someone with a typographical error on their job
description.
2) In New York City, there are 3250 walk buttons on stop lights. It
was found that 77% of those buttons do not work.

9. Practice Set

Page 21 (#5-12)

10. References

Triola, M.F. (2014) Elementary Statistics. Boston, MA: Pearson.