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Unformatted text preview: a population proportion, as p approaches .5, the
calculated value of the sample size ______________.
A. Stays the same
B. Decreases
C. Increases 90. The tolerance interval of 95.44 percent is ________ a 95.44 percent confidence interval.
A. the same width as
B. narrower than
C. wider than 1635 Chapter 01  An Introduction to Business Statistics 91. A random sample of size 30 from a normal population yields
= 32.8 with a population
standard deviation of 4.51. Construct a 95 percent confidence interval for
.
A. [23.96 41.64]
B. [32.04 33.56]
C. [31.45 34.15]
D. [31.19 34.41] 92. A sample set of weights in pounds are 1.01, .95, 1.03, 1.04, .97, .97, .99, 1.01, and 1.03.
Assume the population of weights are normally distributed. Find a 99 percent confidence
interval for the mean population weight.
A. [.965 1.035]
B. [.969 1.031]
C. [.973 1.027]
D. [.941 1.059] 93. A sample of 8 items has an average fat content of 18.6 grams and a standard deviation of
2.4 grams. Assuming a normal distribution, construct a 99 percent confidence interval for .
A. [16.06 21.14]
B. [16.42 20.78]
C. [15.63 21.57]
D. [15.75 21.45] 94. A sample of 12 items yields
= 48.5 grams and s = 1.5 grams. Assuming a normal
distribution, construct a 90 percent confidence interval for the population mean weight.
A. [47.722 49.278]
B. [47.788 49.212]
C. [45.806 51.194]
D. [47.865 49.135] 1636 Chapter 01  An Introduction to Business Statistics 95. A sample of 100 items has a population standard deviation of 5.1 and a mean of 21.6.
Construct a 95 percent confidence interval for .
A. [11.60 31.60]
B. [21.16 22.04]
C. [20.60 22.60]
D. [20.76 22.43] 96. In a survey of 1,000 people, 420 are opposed to the tax increase. Construct a 95 percent
confidence interval for the proportion of those people opposed to the tax increase.
A. [.394 .446]
B. [.389 .451]
C. [.380 .460]
D. [.399 .441] 97. Of a random sample of 600 trucks at a bridge, 114 had bad signal lights. Construct a 98
percent confidence interval for the percentage of trucks that had bad signal lights.
A. [.1754 .2046]
B. [.1740 .2060]
C. [.1572 .2228]
D. [.1527 .2273] 98. The success rate of a procedure is 37 per 120 cases in a sample. Find a 95 percent
confidence interval for the actual success proportion of the procedure.
A. [.2975 .4425]
B. [.2389 .3776]
C. [.2836 .4564]
D. [.2250 .3910] 1637 Chapter 01  An Introduction to Business Statistics 99. What sample size is needed to obtain a 90 percent confidence interval for the mean protein
content of meat if the estimate is to be within 2 pounds of the true mean value? Assume that
the variance is 49 pounds.
A. 34
B. 1625
C. 21
D. 987 100. What sample size is needed to obtain a 95 percent confidence interval for the proportion
of fat in meat that is within 3 percent of the true value?
A. 267
B. 1068
C. 17
D. 545 101. What sample size is needed to estimate the proportion of highway speeders within 5
percent using a 90 percent confidence level?
A. 385
B. 68
C. 271
D. 165 102. What sample size is needed to estimate with 95 percent confidence the mean intake of
calcium within 20 units of the true mean if the intake is normal with a variance of 1900 units?
A. 34,671
B. 187
C. 32
D. 19 1638 Chapter 01  An Introduction to Business Statistics 103. A sample of 200 observations is taken. The mean is 31.7 and the standard deviation is
1.8. Form a 90 percent confidence interval for the population mean.
A. [31.54 31.86]
B. [28.74 34.66]
C. [28.53 34.87]
D. [31.49 31.91] 104. Ten items of 100 are defective. Develop a 95 percent confidence interval for the
population proportion of defectives.
A. [.04 .16]
B. [.09 .11]
C. [.08 .12]
D. [.02 .18] 105. What is a 95 percent confidence interval for µ when n = 10,
Assume population normality.
A. [26.44 44.76]
B. [26.30 44.90]
C. [33.02 38.18]
D. [27.54 43.66] 106. What is a 99.9 percent confidence interval for µ when n = 10,
Assume population normality.
A. [29.75 38.45]
B. [31.48 36.72]
C. [30.98 37.22]
D. [29.56 38.64] 1639 35.6, and s = 13.0? = 34.1, and s = 3.0? Chapter 01  An Introduction to Business Statistics 107. In a study of 265 subjects, the average score on the examination was 63.8 and s = 3.08.
What is a 95 percent confidence for µ?
A. [63.59 64.01]
B. [57.76 69.84]
C. [63.43 64.17]
D. [63.56 64.04] 108. Given the following test scores, find a 95 percent confidence interval for the population
mean: 148, 154, 158, 160, 161, 162, 166, 170, 182, 195, 236. Assume population normality.
A. [155.24 188.76]
B. [168.64 175.36]
C. [157.25 186.75]
D. [116.41 227.59] 109. Find the 99 percent confidence interval for p when
A. [.068 .332]
B. [.097 .303]
C. [.159 .241]
D. [.147 .253] = .2, and n = 100. 110. Find a 98 percent confidence interval for p when
A. [.206 .294]
B. [.231 .269]
C. [.228 .272]
D. [.200 .300] = .25 and n = 400. 111. Find a 99 percent confidence interval for p when
A. [.469 .551]
B. [.490 .530]
C. [.446 .574]
D. [.235 .785] = .51 and n = 1,000. 1640 Chapter 01  An Introduction to Business Statistics 112. In a survey of 400 people, 60 percent favor new zoning laws. Find a 95...
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 Winter '14

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