| Key Learning Goals for this Lesson: |
Textbook reading: Chapter 8: Model Inference and Averaging (sections 8.1, 8.2, 8.3, and 8.5.1 only) |
Definitions
Population: A collection of all individuals about which information is desired.
Random Sample: A subset of the population selected.
Parameter: A numerical value associated with a population.
Statistic: A numerical value computed from a sample.
We want to know the parameter. But, in most cases, it is hard to know the parameter since the population is too large. Thus, we need to estimate the parameter by some proper statistic(s) computed from the sample.
Self-check
Think About It!
In each situation, explain whether the value given in bold print is a statistic or a parameter - then click the icon on the left to reveal the answer.
1. A polling organization samples 1000 adults nationwide and finds that 72% of those sampled favor tougher penalties for persons convicted of drunk driving.
2. In their year 2000 census, the United States Census Bureau found that the median age of all American citizens was about 35 years.
3. For a sample of 20 men and 25 women, there is a 14 centimeter difference in the mean heights of the men and women.
4. A writer wants to know how many typing mistakes there are in his manuscript, so he hires a proofreader who reads the entire manuscript and finds 15 errors.