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| 1 | |
A point estimate is |
| | A) | Always an estimate of the population mean. |
| | B) | Always equal to the population value. |
| | C) | An estimate of the population parameter. |
| | D) | None of the above. |
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| 2 | |
A confidence interval |
| | A) | Always includes the population parameter. |
| | B) | Decreases in width as the sample size is increased. |
| | C) | Cannot include a value of 0. |
| | D) | None of the above. |
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| 3 | |
If we wished to decrease the width of a confidence interval, we would not do which of the following: |
| | A) | Increase the size of the sample. |
| | B) | Reduce the size of the population. |
| | C) | Decrease the level of confidence. |
| | D) | None of the above. |
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| 4 | |
We wish to develop a confidence interval for the population mean. The shape of the population is not known, but we have a sample of 40 observations. We decide to use the 92 percent level of confidence. What is the appropriate value of z? |
| | A) | 1.96 |
| | B) | 1.65 |
| | C) | 2.58 |
| | D) | 1.75 |
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| 5 | |
Which of the following statements is not a characteristic of the t distribution? |
| | A) | It is a continuous distribution. |
| | B) | It has a mean of 0. |
| | C) | It is symmetrical. |
| | D) | Like z, there is only one t distribution. |
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| 6 | |
We wish to develop a confidence interval for the population mean. The population follows the normal distribution, we know the population standard deviation, and have a sample of 10 observations. We decide to use the 90 percent level of confidence. The appropriate value to represent the level of confidence is |
| | A) | z = 1.645 |
| | B) | z = 1.96 |
| | C) | t = 1.833 |
| | D) | t = 1.812 |
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| 7 | |
The fraction or ratio of a sampling possessing a certain trait is called a |
| | A) | Population. |
| | B) | Mean. |
| | C) | Confidence interval. |
| | D) | Proportion |
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| 8 | |
To develop a confidence interval for a proportion (when np and n(1- p), both exceed 5) |
| | A) | We need to meet the binomial conditions. |
| | B) | The sample should be at least 100. |
| | C) | p should be less than .05. |
| | D) | None of the above. |
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| 9 | |
The finite population correction factor is used when |
| | A) | n is more than 30. |
| | B) | N is more than 1,000. |
| | C) | np is greater than 5. |
| | D) | n/N is more than .05. |
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| 10 | |
We wish to estimate the population proportion. We want to be 95 percent confident of our results and we want the estimate to be within .01 of the population parameter. No estimate of the population proportion is available. What value should we use for p? |
| | A) | 1.96 |
| | B) | .01 |
| | C) | .50 |
| | D) | We cannot complete the problem, we need more information. |
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| 11 | |
The United Travel Agency wishes to make an estimate regarding the number of nights a family spends away from home while on vacation during the summer months. A sample of 50 families revealed a mean of 4.75 nights with a standard deviation of 1.90 nights. Develop a 96 percent confidence interval for the population mean. |
| | A) | 1.43, 8.08 |
| | B) | 4.28, 5.22 |
| | C) | 3.00, 6.50 |
| | D) | None of the above. |
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| 12 | |
In a study of employee benefits, a sample of 120 companies in the Denver area showed 36 provided baby-sitting on site for employees. Develop a 95 percent confidence interval for the proportion of all companies in the Denver area providing baby-sitting. |
| | A) | .22, .38 |
| | B) | .26, .34 |
| | C) | 3.00, 6.50 |
| | D) | None of the above. |
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| 13 | |
In a recent Met-Life study of 15 dental claims, the mean amount paid per claim was $425, with a standard deviation of $120. Develop a 99 percent confidence interval for the population mean. |
| | A) | 345, 505 |
| | B) | 364, 486 |
| | C) | 333, 517 |
| | D) | None of the above. |
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| 14 | |
The owner of Tony's Pizza wanted to estimate the mean time it takes customers to receive their pizza delivered to their home. How large a sample is required to estimate is to be within 2 minutes, with a 99 percent level of confidence? The standard deviation is estimated to be 7 minutes. |
| | A) | 82 |
| | B) | 47 |
| | C) | 49 |
| | D) | None of the above. |
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| 15 | |
The time taken to drive to work by the employees of a software firm is normally distributed. A sample of 64 workers had a mean of 28 minutes with a standard deviation of 16 minutes. What is the upper limit of the 99% confidence interval for the mean? |
| | A) | 33.16 |
| | B) | 32 |
| | C) | 28.25 |
| | D) | 31.29 |
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| 16 | |
The weight of salmon caught in BC is normally distributed. A sample of 36 has a mean of 4 kg and a standard deviation of 1.2 kg. What is the lower limit of the 95% confidence interval for the mean? |
| | A) | 3.608 |
| | B) | 3.8 |
| | C) | 3.556 |
| | D) | 3.533 |
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| 17 | |
A pollster wishes to estimate the proportion of voters who prefer the Green Party to any other. Prior sampling indicates that about 15% do. How big a sample should be taken to be 90% certain of estimating the correct proportion within 2 percentage points? |
| | A) | 863 |
| | B) | 1,691 |
| | C) | 524 |
| | D) | 1225 |
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