Chapter 8: Quiz

 1. The absolute value of the difference between the point estimate and the population parameter it estimates is   A. standard error B. sampling error C. precision D. error of confidence E. none of the above 2. A probability statement about the sampling error is known as the   A. confidence B. precision C. interval D. error E. none of the above 3. If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient is   A. 0.485 B. 1.96 C. 0.95 D. 1.645 E. none of the above 4. The variance of a population is known to be 400.  At 95% confidence, the margin of error will be  A. 39.2 or less B. 3.92 or less C. 3.29 or less D. 78.4 or less E. none of the above 5. In order to estimate the average time spent on the computer terminals per student at a local university, data were collected for a sample of 81 business students over a one week period.  Assume the population standard deviation is 1.2 hours.  With a 0.95 probability, the margin of error is approximately  A. 7.5 B. 0.014 C. 0.160  D. 0.2613 6. In order to estimate the average time spent on the computer terminals per student at a local university, data were collected for a sample of 81 business students over a one week period.  Assume the population standard deviation is 1.2 hours.  If the sample mean is 9 hours, then the 95% confidence interval is     A. 7.04 to 110.96 hours B. 7.36 to 10.64 hours C. 7.80 to 10.20 hours D. 8.74 to 9.26 hours 7. The t value with a 95% confidence and 24 degrees of freedom is   A. 1.711 B. 2.064 C. 2.492 D. 2.069 E. none of the above 8. A 95% confidence interval for a population mean is determined to be 100 to 120.  If the confidence coefficient is reduced to 0.90, the interval for m  A. becomes narrower B. becomes wider C. does not change D. becomes 0.1 E. none of the above 9. A sample of 16 elements from a normally distributed population is selected.  The sample mean is 10 with a standard deviation of 4.  The 95% confidence interval for m is     A. 8.040 to 11.96 B. 1.476 to 18.524 C. 2.160 to 17.840 D. 7.869 to 12.131 E. none of the above 10. A random sample of 144 observations has a mean of 20, a median of 21, and a mode of 22.  The population standard deviation is known to equal 4.8.  The 95.44% confidence interval for the population mean is    A. 15.2 to 24.8 B. 19.200 to 20.800 C. 19.216 to 20.784 D. 21.2 to 22.8 E. none of the above