# Exam 3 Study Guide: Chapters 7-8

1. A graph of a probability distribution is given along with a critical value and level of significance. Draw and label a vertical line at the critical value, shade and label the critical region, label the non-critical region, label each region with the area in that region, write "Reject H0" and "Retain H0" in the appropriate regions of the graph. Also, identify whether it is a left tail, right tail, or two-tail test. Most of this is in your notes and the graphs from the activities.
2. Five claims are written symbolically. Determine whether the given statement is the null hypothesis or the alternative hypothesis.
3. Five statements are given. For each one, decide whether the statement is the null or alternative hypothesis. These are English statements like "The defendant is innocent", not mathematical ones like "12% of adults wet their bed". Remember that the null hypothesis is the normal or assumed condition.
4. Five statements are given. For each one, decide whether it represents a type I or type II error. For example, "A blood test comes back negative (not infected) when the person really is infected" is a type II error because the normal condition of a person is that they are not infected. Since they actually are infected, the null hypothesis is false and we are retaining a false null hypothesis.
5. Three p-values and significance levels are given. In each case, decide whether to reject or retain the null hypothesis.
6. Five critical value(s) and test statistics are given. For each case, decide whether it is a left tail, right tail, or two tail test and whether to Reject H0 or Retain H0.
7. A test statistic and the area to either the left or right of the test statistic are given. Give the p-value for a left tail test, a right tail test, and a two tail test.
8. Three confidence intervals are given along with a null hypothesis. Decide whether the test is left tailed, right tailed, or two tailed and whether you would reject or retain the null hypothesis.
9. Circle the correct responses so that the conclusion is properly worded. Three parts.
10. Know the concept that is fundamental to all hypotheses testing.
11. Five claims are given. For each claim, write the null and alternative hypotheses and determine whether it is a left tail, right tail, or two tail test. These are mathematical statements like "the average adult earns \$35,000 a year". They could be about one or two proportions or means. If there are two samples, be sure to define the subscripts or use subscripts that make sense.
12. Work a hypothesis test. It could be about one or two proportions or means. Write the original claim symbolically and decide if it is the null or alternative hypothesis. Write H0 and H1 and identify it as a left tail, right tail, or two tail test. Identify key values from the problem. The test statistic, p-value, and/or confidence interval from Minitab are given, use them to make a decision and then write the conclusion. Look at activities 6 and 7, the chapter 7 homework and chapter 8 homework. When you need a critical value, there is a portion of the table given.
13. Similar to #12
14. Similar to #12

## Notes

• You will probably want a calculator for the test although the hardest calculations involve simple arithmetic (subtracting from 1, multiplying or dividing by 2).
• You will not need to compute any test statistics or confidence intervals for the test. You will need to know how to interpret them.
• In questions 12, 13, and 14, two tail probabilities from Minitab are given. If your hypothesis test is a one tail test, then you will need to divide the p-value by two.
• There is only one problem where you need to find a critical value and the relevant portions of the table are included on the test.
• You may want to review the hypothesis testing assessment.

## Points per problem

 # Pts 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Total 7 5 5 5 3 10 3 6 9 2 10 13 13 9 100