TRUE OR FALSE
1. True or false: In a dependent sampling method, the subjects in the first sample determine the subjects for selection in the second sample.
2. True or false: The pooled estimate of , , always lies between and .
3. True or false: The test statistic measures the size of the typical error in using to estimate .
FILL IN THE BLANK
4. The conditions on paired sample data for performing a hypothesis test or constructing a confidence interval on paired sample data are that the population is ___________ or the sample size is ___________.
5. The notation represents the ___________ __________ ___________ (three words).
6. ___________ [notation] represents the sample mean of the set of paired differences.
SHORT ANSWER
7. What is the notation used to indicate the difference in population means for two independent samples?
8. What statistic is used to estimate the common unknown population proportion?
9. If a confidence interval for contains 0, then with confidence, what can you conclude about the difference in the population means?
CALCULATIONS AND INTERPRETATIONS
10. Trying to quit smoking? Butt-Enders, a cigarette dependence reduction program, claims to lower the average number of cigarettes smoked for its participants. A sample of 10 participants smoked the following numbers of cigarettes on a randomly chosen day before and after attending Butt-Enders. Assume that the differences are normally distributed.
| Participant | 1 | 2 | 3 | 4 | 5 |
| Before | 40 | 20 | 60 | 30 | 50 |
| After | 20 | 0 | 40 | 30 | 20 |
| Participant | 6 | 7 | 8 | 9 | 10 |
| Before | 60 | 20 | 40 | 30 | 20 |
| After | 60 | 20 | 20 | 0 | 20 |
11. A family is trying to decide where to move. The choice has come down to Suburb A and Suburb B. A random sample of 40 households in Suburb A had a mean income of $50,000 and a standard deviation of $15,000. A random sample of 36 households in Suburb B had a mean income of $65,000 and a standard deviation of $20,000.
Use the following information for Exercises 12 and 13. A soft drink company recently performed a major overhaul of one of its bottling machines. Management is eager to determine whether the overhaul has resulted in an increase in productivity for the machine. One hundred “minute segments” are sampled at random from the updated machine (sample 1) and a machine that was not updated (sample 2), and the number of bottles processed is noted. The mean and standard deviation of the number of bottles processed by each machine is given in the table.
| Updated machine | |||
| non-updated machine |
12. Construct and interpret a 95% confidence interval for .
13. Refer to the previous exercise.
14. The U.S. Census Bureau reported that, for people 18 to 24 years old, the mean annual income for people who never married was $13,539 and for married people was $19,321. Suppose that this information came from a survey of 100 people from each group and that the sample standard deviations were $5000 for the people who never married and $8000 for the married people.