4/6/2022
Problem Session - getting comfortable with t.test()
Hypothesis Testing - A decision rule based on data
|
Null Hypothesis |
| True |
False |
| Decision |
Reject Null Hypothesis |
Type I Error |
Correct Decision |
| Do Not Reject Null Hypothesis |
Correct Decision |
Type II Error |
Computing Type II error probabilities
- Example - Let p equal the proportion of defective components in a very large shipment sent to a computer company. The company accepts the shipment only if Ho: p =0.1 can be rejected in favor of Ha: p < 0.1 at a significance level of 0.05 based on a sample of 100 components.
- Compute the probability of failing to reject Ho when the actual percentage of defectives is 7%.
- Compute the probability of failing to reject Ho when the actual percentage is 8%.
- Would the probability of failing to reject Ho increase or decrease if the actual percentage is 9%? Explain your response. (Hint: compare the two probabilities you computed above.)
Power Activity
Power and sample size calculations with R
- Download, install, and explore with the pwr package.
- See Power.R to compute the power on the handout with R
- Explore with the pwr package to compute other powers.
Please complete your reading of Chapter 7 for class on Monday.
We will have a quiz on Friday covering Sections 7.1 and 7.2