Lesson 7
1. Lesson 7
1.2. Explore
Module 4: Statistical Reasoning
Explore
The only way to be 100% confident that results represent a population is to measure or survey every member of the population. For example, a census can be conducted and every person in a population can be surveyed. But it is very expensive to conduct a census. It is also very expensive to measure each and every product ever created. For instance, a clothing manufacturer might use a machine to see how much force it takes to rip a pair of pants. If the manufacturer tested every pair of pants they made, there wouldn’t be any pants left to sell. An entire population would be destroyed. Instead, a sample of the population can be tested.
Read “Example 2: Analyzing the effect of sample size on margin of error and confidence intervals” and “Example 3: Analyzing the effect of confidence levels on sample size” on pages 296 to 299 of your textbook. Are the relationships between confidence level and sample size and the margin of error and sample size consistent with those relationships you found in Try This 1?
Self-Check 1
Complete the following statements, and then compare your answers with the ones provided. You may want to file this information in your course folder for future reference.
- Fill in the blanks in the following statements.
- For a given confidence level, a larger sample results in a ________________ margin of error.
- When the confidence level is decreased, the size of the sample required for a given confidence interval ________________.
- For a given sample size, the margin of error increases as the confidence level ________________.
- Population has the greatest affect on sample size when the population size is ________________.
Answer - For a given confidence level, a larger sample results in a ________________ margin of error.