$7.00 A news magazine claims that 30% of all New York City police officers are overweight
Found in Mathematics: StatisticsChapter 1, # 0
1.)A news magazine claims that 30% of all New York City police officers are overweight. Indignant at this claim, the New York City police commissioner conducts a survey in which 200 randomly selected New York City police officers are weighed. 52, or 26%, of the surveyed officers turn out to be overweight. Which of the following statements about this situation is true?
| 1) | The number 26% is a statistic. |
| 2) | The number 30% is a statistic. |
| 3) | It is not true that 30% of the officers are overweight. |
| 4) | The number 26% is a parameter. |
2.)In a simple random sample of 1000 Americans, it was found that 61% were satisfied with the service provided by the dealer from which they bought their car. In a simple random sample of 1000 Canadians, 58% said that they were satisfied with the service provided by their car dealer. Which of the following statements concerning the sampling variability of these statistics is true?
| 1) | The sampling variability is about the same in both cases. |
| 2) |
The sampling variability is much smaller for the statistic based on the sample of 1000 Canadians since the population of Canada is smaller than that of the United States, and therefore the sample is a larger proportion of the population.
|
| 3) | The sampling variability is much larger for the statistic based on the sample of 1000 Canadians, since Canada has a lower population density than the United States, and having subjects living farther apart always increases sampling variability. |
| 4) | We can not tell the sampling variability, since the standard deviation for the population is not given. |
3.)Suppose that you are a student worker in the statistics department and agree to be paid according to the "random pay" system. Each week, the chair of the department flips a coin. If the coin comes up heads, your pay for the week is $80; if it comes up tails, your pay for the week is $40. You work for the department for 100 weeks (at which point you have learned enough probability to know that the "random pay" system is not to your advantage). The probability that X-bar, your average earnings in the first two weeks, is greater than $65 is
| 1) | 0.2500. |
| 2) | 0.3333. |
| 3) | 0.5000. |
| 4) | 0.7500 |
4.)The sampling distribution of the sample mean, X-bar, is formed from random samples of size 16 taken from a population with a mean of 64 and standard deviation of 10. What are the mean and standard deviation of the sampling distribution of X-bar, the sample mean?
| 1) | mean = 64, standard deviation = 0.625 |
| 2) | Mean=13, standard deviation=0.625 |
| 3) | mean = 8, standard deviation = 2.5 |
| 4) | mean = 64, standard deviation = 2.5 |
5.)The duration of Alzheimer's disease, from the onset of symptoms until death, ranges from 3 to 20 years, with a mean of 8 years and a standard deviation of 4 years. The administrator of a large medical center randomly selects the medical records of 30 deceased Alzheimer's patients and records the duration of the disease for each one. Find the probability that the average duration of the disease for the 30 patients will exceed 8.25 years.
| 1) | 0.2491 |
| 2) | 0.6331 |
| 3) | 0.3669 |
| 4) | 0.4761 |
6.)The duration of Alzheimer's disease, from the onset of symptoms until death, ranges from 3 to 20 years, with a mean of 8 years and a standard deviation of 4 years. The administrator of a large medical center randomly selects the medical records of 30 deceased Alzheimer's patients and records the duration of the disease for each one. Find the probability that the average duration of the disease for the 30 patients will lie within 1 year of the overall mean of 8 years.
| 1) | 0.8294 |
| 2) | 0.1706 |
| 3) | 0.4147 |
| 4) | 1.2313 |
Question 7 is a short answer, looking for ideas
- 7.) A researcher states that in a survey of 100 employers, she found that 75% of the respondents said that a college degree is essential for employment. How would you find a 95% confidence interval and in your own words, how would you explain what that means?
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- Posted on Jun. 20, 2010 at 12:12:27AM
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