Week 7 – Inference for Regression
📖 Required Reading: Introduction to Modern Statistics – Study Design
3. Which of the following statements are true about observational studies and experiments? Select all that apply!
- Experiments randomly assign the explanatory variable
- Observational studies randomly assign the explanatory variable
- Observational studies can make causal statements about the relationship between the explanatory and response variables
- Experiments can make causal statements about the relationship between the explanatory and response variables
4. What are different methods for sampling from a population? Select all that apply!
- simple random sampling
- stratified random sampling
- cluster sampling
- multistage sampling
- convenience sampling
5. Cluster sampling and stratified sampling both rely on grouping observations, but have important differences. Match each method to how observations are randomly sampled.
stratified sampling
cluster sampling
groups of observations are created, groups are randomly selected, every observation in the selected group is sampled
groups of observations are created, observations within a group are randomly sampled
1 Textbook Reading – Part 1
Required Reading: Exploring Sampling Variability
2 Textbook Reading – Part 2
Required Reading: Confidence Intervals for the Slope
3 Concept Quiz – Due Wednesday by the beginning of class (note the new time!)
1. Match each item to it’s respective analogy:
point estimate
confidence interval
fishing with a net
fishing with a spear
2. To create a 95% confidence interval using the percentile method, what percentiles of the bootstrap distribution do you need to calculate?
- 0th
- 2.5th
- 5th
- 90th
- 95th
- 97.5th
3. To create a 95% confidence interval using the standard error method, what standard error do you use?
- the sample standard deviation
- the bootstrap distribution standard deviation
- a resample standard deviation
- 1.96
4. We almost never know if our confidence interval captured the true population parameter.
- True
- False
5. What percentage of 99% confidence intervals do you expect to capture the true population parameter?
6. The word “confident” in a confidence interval interpretation corresponds to what aspect of the interval?
- the accuracy of the original sample
- the reliability of the procedure for constructing confidence intervals
- the precision of the bootstrap samples
7. Which of the following are true?
- Smaller sample sizes tend to produce narrower confidence intervals.
- Smaller sample sizes tend to produce wider confidence intervals.
- Lower confidence levels tend to produce wider confidence intervals.
- Lower confidence levels tend to produce narrower confidence intervals.
8. In a regression table, what does the “std_error” value associated with the slope represent?
- the standard deviation of the sample
- the standard deviation of the bootstrap distribution
- the estimated standard deviation of the sampling distribution
- the standard error of the sample
9. In a regression table, how is the “std_error” value calculated?
- a mathematical formula
- the standard deviation of the sample
- the standard deviation of the bootstrap distribution
10. What percentage confidence interval is output in a regression table?
- 99%
- 95%
- 90%