# OSU BUSMGT 2320 - sampleexam2 (9 pages)

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- Pages:
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- School:
- Ohio State University
- Course:
- Busmgt 2320 - Decision Sciences: Statistical Techniques

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1 The average monthly electric bill of a random sample of 256 residents of a city is 90 with a standard deviation of 24 a Construct a 90 confidence interval for the mean monthly electric bills of all residents b Construct a 95 confidence interval for the mean monthly electric bills of all residents Answers a 87 5325 to 92 4675 b 87 06 to 92 94 2 In a random sample of 400 registered voters 120 indicated they plan to vote for Candidate A Determine a 95 confidence interval for the proportion of all the registered voters who will vote for Candidate A Answer 0 255 to 0 345 3 A sample of 100 cans of coffee showed an average weight of 13 ounces with a standard deviation of 0 8 ounces a Construct a 95 confidence interval for the mean of the population Answers a 12 8432 to 13 1568 4 A random sample of 121 checking accounts at a bank showed an average daily balance of 300 and a standard deviation of 44 Develop a 95 confidence interval estimate for the mean of the population Answer 292 16 to 307 84 5 A sample of 51 observations will be taken from an infinite population The population proportion equals 0 85 The probability that the sample proportion will be between 0 9115 and 0 946 is a 0 8633 b 0 6900 c 0 0819 d 0 0345 Answer c 6 A finite population correction factor is needed in computing the standard deviation of the sampling distribution of sample means a whenever the population is infinite b whenever the sample size is more than 5 of the population size c whenever the sample size is less than 5 of the population size d The correction factor is not necessary if the population has a normal distribution Answer b 7 Four hundred people were asked whether gun laws should be more stringent Three hundred said yes and 100 said no The point estimate of the proportion in the population who will respond yes is a 300 b approximately 300 c 0 75 d 0 25 Answer c 8 A population has a mean of 300 and a standard deviation of 18 A sample of 144 observations will be taken The probability that the sample mean will be between 297 to 303 is a 0 4332 b 0 8664 c 0 9332 d 0 0668 Answer b 9 A population of 1 000 students spends an average of 10 50 a day on dinner The standard deviation of the expenditure is 3 A simple random sample of 64 students is taken a What are the expected value standard deviation and shape of the sampling distribution of the sample mean b What is the probability that these 64 students will spend a combined total of more than 715 21 c What is the probability that these 64 students will spend a combined total between 703 59 and 728 45 Answers a 10 5 b 0 0314 c 0 0794 0 363 normal 10 The life expectancy in the United States is 75 with a standard deviation of 7 years A random sample of 49 individuals is selected a What is the probability that the sample mean will be larger than 77 years b What is the probability that the sample mean will be less than 72 7 years c What is the probability that the sample mean will be between 73 5 and 76 years d What is the probability that the sample mean will be between 72 and 74 years e What is the probability that the sample mean will be larger than 73 46 years Answers a 0 0228 b 0 0107 c 0 7745 d 0 1573 e 0 9389 11 The SAT scores have an average of 1200 with a standard deviation of 60 A sample of 36 scores is selected a What is the probability that the sample mean will be larger than 1224 b What is the probability that the sample mean will be less than 1230 c What is the probability that the sample mean will be between 1200 and 1214 d What is the probability that the sample mean will be greater than 1200 e What is the probability that the sample mean will be larger than 73 46 Answers a 0 0082 b 0 9986 c 0 4192 d 0 5 e 1 0 12 MNM Corporation gives each of its employees an aptitude test The scores on the test are normally distributed with a mean of 75 and a standard deviation of 15 A simple random sample of 25 is taken from a population of 500 a What are the expected value the standard deviation and the shape of the sampling distribution of x b What is the probability that the average aptitude test in the sample will be between 70 14 and 82 14 c What is the probability that the average aptitude test in the sample will be greater than 82 68 d What is the probability that the average aptitude test in the sample will be less than 78 69 e Find a value C such that P x C 015 Answers a 75 3 normal b 0 9387 c 0 0052 d 0 8907 e 81 51 13 Michael is running for president The proportion of voters who favor Michael is 0 8 A simple random sample of 100 voters is taken a What are the expected value standard deviation and shape of the sampling distribution of p b What is the probability that the number of voters in the sample who will not favor Michael will be between 26 and 30 c What is the probability that the number of voters in the sample who will not favor Michael will be more than 16 Answers a 0 8 0 04 normal b 0 0606 c 0 8413 14 In a restaurant the proportion of people who order coffee with their dinner is 0 9 A simple random sample of 144 patrons of the restaurant is taken a What are the expected value standard deviation and shape of the sampling distribution of p b What is the probability that the proportion of people who will order coffee with their meal is between 0 85 and 0 875 c What is the probability that the proportion of people who will order coffee with their meal is at least 0 945 Answers a 0 9 0 025 normal b 0 1359 c 0 0359 15 A random sample of nine telephone calls in an office provided the following information Call Number 1 2 3 4 5 6 7 8 9 a b c d Duration In Minutes 3 8 4 3 5 6 3 5 8 Type of Call local long distance local local long distance local local local local Determine the point estimate for the average duration of all calls What is the point estimate for the standard deviation of the population Determine the standard error of the mean What is the point estimate for the proportion of all calls that were long distance e Determine the standard …

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