Chapter 1 Extra Practice
1.1 Introduction to Statistics
1. Determine how the key terms apply to the following study. We want to know the average (mean) amount of money first-year college students spend at ABC College on school supplies (excluding books). We randomly survey 100 first-year students at the college. Three of those students spent $150, $200, and $225.
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2. Determine how the key terms apply to the following study. We want to know the average (mean) amount of money spent on school uniforms each year by families with children at Knoll Academy. We randomly survey 100 families with children in the school. Three of the families spent $65, $75, and $95.
3. Determine how the key terms apply to the following study.
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4. As part of a study designed to test the safety of automobiles, the National Transportation Safety Board collected and reviewed data about the effects of automobile crashes on test dummies. Here is the criterion they used:
| Speed at which cars crashed | Location of “driver” (i.e., dummies) |
|---|---|
| 35 miles/hour | Front seat |
Figure 1.12
Cars with dummies in the front seats were crashed into a wall at a speed of 35 miles per hour. We want to know the proportion of dummies in the driver’s seat that would have had head injuries if they had been actual drivers. We start with a simple random sample of 75 cars.[1]
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5. An insurance company would like to determine the proportion of all medical doctors who have been involved in one or more malpractice lawsuits. The company selects 500 doctors at random from a professional directory and determines how many in the sample have been involved in malpractice lawsuits.
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6. Pharmaceutical companies often conduct surveys to determine the effectiveness of a treatment program. Suppose that a new AIDS antibody drug is currently under study. It is given to patients once the AIDS symptoms have revealed themselves. Of interest is the average (mean) length of time in months that patients live once they start the treatment. Two researchers each follow a different set of 40 patients with AIDS from the start of treatment until their deaths. The following data was collected, measuring the time (in months) between patients starting treatment and their deaths.
Researcher A: 3, 4, 11, 15, 16, 17, 22, 44, 37, 16, 14, 24, 25, 15, 26, 27, 33, 29, 35, 44, 13, 21, 22, 10, 12, 8, 40, 32, 26, 27, 31, 34, 29, 17, 8, 24, 18, 47, 33, 34
Researcher B: 3, 14, 11, 5, 16, 17, 28, 41, 31, 18, 14, 14, 26, 25, 21, 22, 31, 2, 35, 44, 23, 21, 21, 16, 12, 18, 41, 22, 16, 25, 33, 34, 29, 13, 18, 24, 23, 42, 33, 29
Determine how the key terms apply to the example for Researcher A.