Arizona State University ECN 212 Exam2 Practice(1). 45 of the commonly tested questions with answer key provided.

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Exam2 Practice Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the questio 1) Which of the following is not a characteristic of a binomial experiment? ... 1) A) Each trial is independent of the other trials in the experiment. B) Each trial has only two possible outcoma esusccess or a failure. C) The experiment consists of a fixed number of trials. D) The probability of a success must exceed the probability of a failure. 2) According to LIMRA, 75% of husband-wife families with kids under 18 years old have life2) insurance. A random sample of six husband-wife families was selected. What is the probability that exactly four families have life insurance? A) 0.3735 B)0.5215 C) 0.4832 D) 0.2966 3) According to LIMRA, 75% of husband-wife families with kids under 18 years old have life3) insurance. A random sample of six husband-wife families was selected. What is the probability that less than two families have life insurance? A) 0.1197 B)0.0046 C) 0.0569 D) 0.1864 4) According to LIMRA, 75% of husband-wife families with kids under 18 years old have life4) insurance. A random sample of six husband-wife families was selected. What is the probability that five or more families have life insurance? A) 0.3667 B) 0.4025 C) 0.6621 D) 0.5340 5) According to LIMRA, 75% of husband-wife families with kids under 18 years old have life5) insurance. A random sample of six husband-wife families was selected. What is the mean of this distribution? A) 5.86 B)3.50 C) 5.28 D) 4.5 6) According to LIMRA, 75% of husband-wife families with kids under 18 years old have life6) insurance. A random sample of six husband-wife families was selected. What is the standard deviation of this distribution? A) 2.029 B) 2.607 C) 1.061 D) 1.758 7) A distribution is useful for calculating the probability that a certain number of ev7e)nts will occur over a specific interval of time or space. A) hypergeometric B) binomial C) normal D) Poisson 8) Assume that the number of pieces of junk mail per day that a person receives in their mai8l )box follows the Poisson distribution and averages 3.5 pieces per day. What is the probability that this person will not receive any junk mail tomorrow? A) 0.0302 B)0.1018 C) 0.0514 D) 0.1698 19) Assume that the number of pieces of junk mail per day that a person receives in their mai9l )box follows the Poisson distribution and averages 3.5 pieces per day. What is the probability that this person will receive one or two pieces of junk mail tomorrow? A) 0.2907 B)0.1019 C) 0.1785 D) 0.1237 10) Which of the following probability distribution is not continuous? 10) A) exponential B) Poisson C) normal D) All of these are continuous probability distributions. 11) The probability distribution is bell-shaped and symmetrical. 11) A) Poisson B)uniform C) normal D) exponential 12) Which of the following statements is true regarding the normal probability distribution? 12) A) The mean is always less than the median. B) The mean is always greater than the median. C) The mean and median are roughly equal to one another. D) The mean is always greater than the mode. 13) Suppose the round-trip airfare between Philadelphia and Los Angeles a month before the13) departure date follows the normal probability distribution with a mean of $387.20 and a standard deviation of $68.50. What is the probability that a randomly selected airfare between these two cities will be less than $300? A) 0.2005 B)0.4286 C) 0.3192 D) 0.1020 14) Suppose the round-trip airfare between Philadelphia and Los Angeles a month before the14) departure date follows the normal probability distribution with a mean of $387.20 and a standard deviation of $68.50. What is the probability that a randomly selected airfare between these two cities will be between $325 and $425? A) 0.2650 B)0.5274 C) 0.1548 D) 0.3875 15) A survey conducted in 2011 asked employed adults from age 25 to 70 if they plan to keep1a5)foot in the working world after retirement. Thirty-three percent of the respondents answered "very likely". A random sample of 75 adults from this age group was asked the same question. Using the normal approximation to the binomial distribution, what is the probability that 21 or fewer adults from this sample would very likely plan to keep a foot in the working world after retirement? A) 0.4721 B)0.3192 C) 0.1075 D) 0.2119 16) A discrete random variable that follows the Poisson distribution with a meanheaqsual to 16) counterpart continuous random variable that follows the distribution with a mean equal to µ= 1/ . A) uniform B) discrete C) normal D) exponential 17) In sampling, everythkmember of the population is chosen for the sample. 17) A) probability B)nonprobability C) cluster D) systematic 218) In sampling, we divide the population into mutually exclusive groups and random1l8y) sample from each of these groups. A) cluster B)stratified C) probability D) simple random 19) The average weight of the entire batch of the boxes of cereal filled today was 18.03 ounce1s9.)A random sample of four boxes was selected with the following weights: 18.02, 18.12, 18.10, and 18.08. The sampling error for this sample is . A) 0.05 B)0.02 C) 0.00 D) - 0.04 20)The Central Limit Theorem (CLT) states that the 20) A) sample means of any samples will be uniformly distributed regardless of the shape of their population distributions. B) sample means of large-sized samples will be normally distributed regardless of the shape of their population distributions. C) sample means of any samples will be normally distributed regardless of the shape of their population distributions. D) sample means of large-sized samples will be uniformly distributed regardless of the shape of their population distributions. 21) As the size of the sample increases, 21) A) the population standard deviation increases. B) the standard error of the mean becomes smaller. C) the sampling error increases. D) the shape of the sampling distribution becomes wider. 22)The finite population correction factor for the standard error of the mean should be used 2w2h)en the ratio of the sample size to the size of the population exceeds . A) 2% B)1% C) 3% D) 5% 23)ClearBags is an online company that sells packaging materials for photographers. Suppos2e3t)heir average order size is $210.18 with a standard deviation of $64.21. A random sample of 32 customer orders has been selected. The standard error of the mean for this sample is . A) $64.21 B)$15.80 C) $25.40 D) $11.35 24)According to R.L. Polk & Co., the average age of cars and light trucks in the U.S. in 2011 2w4a)s 10.8 years. Assume that the standard deviation for this population is 3.7 years. A sample of 35 randomly selected vehicles was selected. What is the probability that the sample mean will be greater than 10 years? A) 0.9846 B) 0.5469 C) 0.7812 D) 0.8997 25) The MBA program at Dover College has an enrollment of 160 students with an average ag2e5)of 34.7 years old and a standard deviation 5.2 years. A random sample of 40 MBA students was selected. What is the probability that the average age of the sample is less than 34 years old? A) 0.3300 B) 0.2946 C) 0.1635 D) 0.4443 326)The national average price for regular gasoline in February 2012 was reported to be $3.5226p)er gallon. The standard deviation for the price of regular gasoline was $0.08. A random sample of 30 gas stations had an average price of $3.59. Which of the following statements is correct? A) The interval that contains 95% of the sample means is $3.44 and $3.60. Because the sample mean is between these two values, we have support that the average price for regular gasoline is $3.52. B) The interval that contains 95% of the sample means is $3.47 and $3.57. Because the sample mean is not between these two values, we have support that the average price for regular gasoline is $3.52. C) The interval that contains 95% of the sample means is $3.44 and $3.60. Because the sample mean is not between these two values, we do not have support that the average price for regular gasoline is $3.52. D) The interval that contains 95% of the sample means is $3.49 and $3.55. Because the sample mean is not between these two values, we do not have support that the average price for regular gasoline is $3.52. 27) The sampling distribution of the proportion follows the normal distribution when the valu2e7s)np and nq are greater than or equal to . A) 20 B)50 C) 5 D) 30 28)According to IDC, Apple's share of the smartphone market was 20% durrdinqguath rte r3of 2011.28) A random sample of 115 smartphone users was selected. The standard error of the proportion is . A) 0.0690 B)0.0157 C) 0.0373 D) 0.1016 29)According to IDC, HP controls 34% of the color inkjet printer market worldwide. A random29s)ample of 150 inkjet users was selected. What is the probability that 45 or fewer of these individuals used an HP printer? A) 0.0217 B) 0.1515 C) 0.2236 D) 0.0749 30)According to the Gallup Crime survey, 23% of gun owners in 2011 were women. From a r3an 0)dom sample of 240 gun owners, 47 were female. Which of the following statements is correct? A) The interval that contains 95% of the sample proportions is 0.177 and 0.283. Because the sample proportion is not between these two values, we do not have support that the proportion of gun owners who are female is 23%. B) The interval that contains 95% of the sample proportions is 0.2039 and 0.2561. Because the sample proportion is not between these two values, we do not have support that the proportion of gun owners who are female is 23%. C) The interval that contains 95% of the sample proportions is 0.2039 and 0.2561. Because the sample proportion is between these two values, we have support that the proportion of gun owners who are female is 23%. D) The interval that contains 95% of the sample proportions is 0.177 and 0.283. Because the sample proportion is between these two values, we have support that the proportion of gun owners who are female is 23%. 431) A is defined as the probability that the interval estimate will include the populatio3n1) parameter of interest, such as a mean or a proportion. A) confidence level B)confidence interval C) margin of error D) significance level 32)When calculating a confidence interval for the mean using a sample size of 30 or more wi3th2)a known population standard deviation, the is used. A) Poisson distribution B)normal distribution C) Student's t-distribution D) binomial distribution 33)A random sample of 50 business students required an average of 43.4 minutes to complet3e3a) statistics exam. Assume that the population standard deviation to complete the exam was 8.7 minutes. The standard error of the mean for this sample is . A) 0.66 B)1.87 C) 2.19 D) 1.23 34)A random sample of 30 business students required an average of 43.4 minutes to complet3e4a) statistics exam. Assume that the population standard deviation to complete the exam was 8.7 minutes. The 95% confidence interval around this sample mean is . A) (42.0, 44.8) B)(41.4, 45.4) C) (40.3, 46.5) D) (40.8, 46.0) 35) A represents the width of the confidence interval between a sample mean and its3u5p)per limit or between a sample mean and its lower limit. A) significance level B)margin of error C) confidence interval D) confidence level 36)Increasing the sample size when calculating a confidence interval while keeping the confi3d6e)nce level constant will A) reduce the margin of error resulting in a wider (less precise) confidence interval. B) increase the margin of error resulting in a wider (more precise) confidence interval. C) increase the margin of error resulting in a narrower (more precise) confidence interval. D) reduce the margin of error resulting in a narrower (more precise) confidence interval. 37) The critical z-score for a 98% confidence level is . 37) A) ± 2.575 B)± 2.33 C) ± 1.96 D) ± 1.28 38)When calculating a confidence interval for the mean using a sample size of less than 30 w3it8h) an unknown population standard deviation, the is used. A) binomial distribution B)Student's t-distribution C) normal distribution D) Poisson distribution 39) A random sample of 12 roundtrip flights between Philadelphia and Dallas has an average3a9ir)fare of $483.10 with a sample standard deviation of $52.30. The approximate standard error of the mean for this sample is . A) $15.12 B)$20.44 C) $23.81 D) $17.60 540)A random sample of 20 roundtrip flights between Philadelphia and Dallas has an average4a0ir)fare of $470.40 with a sample standard deviation of $58.70. The margin of error for a 90% confidence interval around this sample mean is . A) 12.0 B)16.1 C) 14.8 D) 22.7 41) A random sample of 20 roundtrip flights between Philadelphia and Dallas has an average4a1ir)fare of $470.40 with a sample standard deviation of $58.70. The critical value for an 80% confidence interval around this sample mean is . A) 1.325 B)0.860 C) 1.328 D) 0.861 42) A random sample of 20 roundtrip flights between Philadelphia and Dallas has an average4a2ir)fare of $470.40 with a sample standard deviation of $58.70. The 95% confidence interval around this sample mean is . A) ($431.01, $509.79) B)($417.88, $522.92) C) ($442.92, $497.88) D) ($457.27, $483.53) 43)"Gamers" are described as people who regularly play video games. A random sample of 14230)people was selected and 66 were found to be male. The 90% confidence interval for the proportion based on this sample is . A) (0.527, 0.573) B)(0.390, 0.710) C) (0.413, 0.687) D) (0.475, 0.625) 44)The National Center for Education would like to estimate the average student debt for the44c)lass of 2010 for the state of Ohio with a 90% confidence interval and a margin of error within plus or minus $1,500. Assuming the standard deviation for student debt in this state is $9,000, the required sample size is . A) 57 B)98 C) 75 D) 66 45)A statistics professor has 115 students in a statistics class and would like to estimate the 4n5u)mber of hours each student studied for the last exam. A random sample of 41 students was found to study an average of 7.3 hours with a standard deviation of 1.9 hours. The 98% confidence interval to estimate the average number of hours studying for the exam is . A) (6.72, 7.88) B)(5.82, 8.79) C) (6.11, 8.49) D) (5.18, 9.42) Answer Key [Show More]

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