Unformatted text preview: ate a 90 percent confidence interval for
.
A. [.927 1.473]
B. [.848 1.552]
C. [.992 1.408]
D. [1.045 1.355] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ unknown 1704 = Chapter 01  An Introduction to Business Statistics 130. A random sample of size 15 is taken from a population assumed to be normal, and
1.2 and s = .6. Calculate a 98 percent confidence interval for
.
A. [.675 1.725]
B. [.794 1.606]
C. [.876 1.524]
D. [.882 1.518] = AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ unknown 131. A random sample of size 15 is taken from a population assumed to be normal, and
1.2 and the sample variance is .36. Calculate a 99 percent confidence interval for
.
A. [.923 1.477]
B. [.794 1.607]
C. [.801 1.600]
D. [.739 1.661] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ unknown 132. If the 95% confidence interval for a mean is from .771 to 1.629, can we conclude that
= .5, using a 95 percent confidence interval?
A. Yes
B. No AACSB: Analytic
Bloom's: Analysis
Difficulty: Medium
Topic: Confidence interval for population mean 1705 = Chapter 01  An Introduction to Business Statistics 133. A PGA (Professional Golf Association) tournament organizer is attempting to estimate
the average number of strokes for the 13th hole on a given golf course. On a particular day, 64
players completed the play on the 13th hole with average of 4.25 strokes and a population
standard deviation of 1.6 strokes. Determine the 95% confidence interval for the average
number of strokes.
A. [3.94 4.56]
B. [3.86 4.64]
C. [4.05 4.45]
D. [3.92 4.58] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ known 134. The quality control manager of a tire company wishes to estimate the tensile strength of a
standard size of rubber used to make a class of radial tires. A random sample of 61 pieces of
rubber from different production batches is subjected to a stress test. The test measures the
force (in pounds) needed to break the rubber. According to the sample results, the average
pressure is 238.4 pounds with a population standard deviation of 35 pounds. Determine the
98% confidence interval.
A. [227.96 248.82]
B. [236.64 240.16]
C. [233.63 243.17]
D. [229.21 247.59] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ known 1706 Chapter 01  An Introduction to Business Statistics 135. An insurance analyst working for a car insurance company would like to determine the
proportion of accident claims covered by the company. A random sample of 240 claims
shows that the insurance company covered 90 accident claims while 150 claims were not
covered. Use a confidence interval of 95% and determine the margin of error.
A. 01513
B. 03125
C. 06125
D. 02965 AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population proportion 136. An insurance analyst working for a car insurance company would like to determine the
proportion of accident claims covered by the company. A random sample of 200 claims
shows that the insurance company covered 80 accident claims while 120 claims were not
covered. Construct a 90% confidence interval estimate of the true proportion of claims
covered by the insurance company.
A. [.356 .444]
B. [.360 .440]
C. [.372 .428]
D. [.343 .457] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population proportion 1707 Chapter 01  An Introduction to Business Statistics 137. A computer manufacturing company has sent a mail survey to 2800 of its randomly
selected customers that have purchased a new personal computer. The survey asked the
customers whether or not they were satisfied with the computer. 800 customers responded to
the survey. 640 customers indicated that they were satisfied, while 160 customers indicated
they were not satisfied with their new computer. Construct a 96% confidence interval estimate
of the true proportion of customers satisfied with their new computer.
A. [.786 .814]
B. [.788 .812]
C. [.775 .825]
D. [.785 .816] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population proportion 1708 Chapter 01  An Introduction to Business Statistics 138. A car insurance company would like to determine the proportion of accident claims
covered by the company. According to a preliminary estimate 60% of the claims are covered.
How large a sample should be taken to estimate the proportion of accident claims covered by
the company if we want to be 98% confident that the sample percentage is within ± 3% of the
actual percentage of the accidents covered by the insurance company?
A. 348
B. 1508
C. 1887
D. 1448 AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Sample size determination for population proportion 139. A statistical quality control process for cere...
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