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STATS Multiple Choice Quiz 2 chap 4 - 7

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Question;MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.1) The collection of all possible events is calledA) the null set. B) a sample space.C) a simple probability. D) a joint probability.2) According to a survey of American households, the probability that the residents own 2 cars if annual hou seholdincome is over $50,000 is 80%. Of the households surveyed, 60% had incomes over $50,000 and 70% had 2 cars. Theprobability that the residents of a household own 2 cars and have an income over $50,000 a year is:A) 0.18 B) 0.12 C) 0.22 D) 0.483) The probability that a new advertising campaign will increase sales is assessed as being 0.80. The probability that thecost of developing the new ad campaign can be kept within the original budget allocation is 0.40. Assuming that the twoevents are independent, the probability that the cost is kept within budget or the campaign will increase sales is:A) 0.32 B) 0.68 C) 0.88 D) 0.204) The employees of a company were surveyed on questions regarding their educational background (col lege degree orno college degree) and marital status (single or married). Of the 600 employees, 400 had college degrees, 100 were single,and 60 were single college graduates. The probability that an employee of the company does not have a college degree i s:A) 0.10 B) 0.67 C) 0.33 D) 0.75TABLE 4-1Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm causedby drunk drivers. A study was recently done that emphasized the problem we all face with drinking and driving. Fourhundred accidents that occurred on a Saturday night were analyzed. Two items noted were the number of vehiclesinvolved and whether alcohol played a role in the accident. The numbers are shown below:Number of Vehicles InvolvedDid alcohol play a role?123TotalsYesNo50100201702517530230Totals75275504005) Referring to Table 4-1, what proportion of accidents involved alcohol or a single vehicle?A) 50/400 or 12.5%B) 195/400 or 48.75%C) 25/400 or 6.25%D) 245/400 or 61.25%6) A company has 2 machines that produce widgets. An older machine produces 23% defective widgets, while the newmachine produces only 8% defective widgets. In addition, the new machine produces 3 times as many wid gets as theolder machine does. Given a randomly chosen widget was tested and found to be defective, what is the probability it wasproduced by the new machine?A) 0.489 B) 0.511 C) 0.15 D) 0.08TABLE 4-2An alcohol awareness task force at a Big-Ten university sampled 200 students after the midterm to ask them whether theywent bar hopping the weekend before the midterm or spent the weekend studying, and whether they did well or poorlyon the midterm. The following result was obtained.Studying for ExamWent Bar HoppingDid Well on Midterm8030Did Poorly on Midterm20707) Referring to Table 4-2, what is the probability that a randomly selected student did well on the midterm or went barhopping the weekend before the midterm?A) (80+30)/200 or 55%B) (30+70)/200 or 50%C) 30/200 or 15%D) (80+30+70)/200 or (110+100-30)/200 or 90%8) Referring to Table 4-2, the events "Did Well on Midterm" and "Did Poorly on Midterm" areA) collective exhaustive. B) statistically dependent.C) mutually exclusive. D) All of the above.9) If two events are mutually exclusive, what is the probability that one or the other occurs?A) 0.50B) 1.00C) 0D) Cannot be determined from the information given.10) If events A and B are mutually exclusive and collectively exhaustive, what is the probability that event A occurs?A) 0B) 1.00C) 0.50D) Cannot be determined from the information given.11) For some positive value of Z, the probability that a standard normal variable is between 0 and Z is 0.3770. The value ofZ is:A) 1.16 B) 0.18 C) 1.47 D) 0.8112) Let X represent the amount of time it takes a student to park in the library parking lot at the university. If we knowthat the distribution of parking times can be modeled using an exponential distribution with a mean of 4 minutes, find theprobability that it will take a randomly selected student more than 10 minutes to park in the library lot.A) 0.917915B) 0.329680C) 0.670320D) 0.08208513) Let X represent the amount of time it takes a student to park in the library parking lot at the university. If we knowthat the distribution of parking times can be modeled using an exponential distribution with a mean of 4 minutes, find theprobability that it will take a randomly selected student between 2 and 12 minutes to park in the library lot.A) 0.656318B) 0.606531C) 0.556744D) 0.04978714) If a particular batch of data is approximately normally distributed, we would find that approximatelyA) 4 of every 5 observations would fall between 1.28 standard deviations around the mean.B) 19 of every 20 observations would fall between 2 standard deviations around the mean.C) 2 of every 3 observations would fall between 1 standard deviation around the mean.D) All of the above.15) Which of the following about the normal distribution is not true?A) Theoretically, the mean, median, and mode are the same.B) Its parameters are the mean,, and standard deviation,.C) About 2/3 of the observations fall within 1 standard deviation from the mean.D) It is a discrete probability distribution.16) For some value of Z, the probability that a standard normal variable is below Z is 0.2090. The value of Z is:A) - 0.31B) 0.31 C) - 0.81D) 1.9617) If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows anormal distribution with a mean of 3.5 minutes and a standard dev iation of 1 minute, find the point in the distribution inwhich 75.8% of the college students exceed when trying to find a parking spot in the library parking lot.A) 3.2 minutes B) 2.8 minutes C) 4.2 minutes D) 3.4 minutes18) Which of the following is true regarding the sampling distribution of the mean for a large sample size?A) It has a normal distribution with the same mean and standard deviation as the population.B) It has the same shape and mean as the po pulation, but has a smaller standard deviation.C) It has a normal distribution with the same mean as the population but with a smaller standard deviation.D) It has the same shape, mean, and standard deviation as the population.19) Major league baseball salaries averaged $3.26 million with a standard deviation of $1.2 million in 2009. Suppose asample of 100 major league players was taken. What was the standard error for the sample mean salary?A) $12 million B) $0.012 millionC) $1,200.0 millionD) $0.12 million20) A telemarketer set the company's computerized dialing system to contact every 25th person listed in the localtelephone directory. What sampling method was used?A) systematic sampleC) stratified sampleB) cluster sampleD) simple random sample21) Which of the following can be reduced by proper interviewer training?A) sampling errorB) measurement errorC) Both of the above.D) None of the above.22) The evening host of a dinner dance reached into a bow l, mixed all the tickets around, and selected the ticket to awardthe grand door prize. What sampling method was used?A) systematic sample B) cluster sampleC) simple random sampleD) stratified sample23) According to a survey of American ho useholds, the probability that the residents own 2 cars if annual householdincome is over $50,000 is 80%. Of the households surveyed, 60% had incomes over $50,000 and 70% had 2 cars. Theprobability that the residents of a household own 2 cars and have an income less than or equal to $50,000 a year is:A) 0.48 B) 0.22 C) 0.18 D) 0.1224) According to a survey of American households, the probability that the residents own 2 cars if annual householdincome is over $50,000 is 80%. Of the households surveyed, 60% had incomes over $50,000 and 70% had 2 cars. Theprobability that the residents of a household do not own 2 cars and have an income over $50,000 a year is:A) 0.48 B) 0.18 C) 0.12 D) 0.2225) The probability that the cost of developing the new ad campaign can be kept within the original budget allocation is0.40. Assuming that the two events are independent, the probability that neither the cost is kept within budget nor thecampaign will increase sales is:A) 0.88 B) 0.32 C) 0.68 D) 0.12TABLE 4-1Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm causedby drunk drivers. A study was recently done that emphasized the problem we all face wi th drinking and driving. Fourhundred accidents that occurred on a Saturday night were analyzed. Two items noted were the number of vehiclesinvolved and whether alcohol played a role in the accident. The numbers are shown below:Number of Vehicles InvolvedDid alcohol play a role?123TotalsYesNo50100201702517530230Totals752755040026) Referring to Table 4-1, given alcohol was involved, what proportion of accidents involved a single vehicle?A) 120/170 or 70.59%C) 50/170 or 29.41%B) 50/75 or 66.67%D) 120/400 or 30%27) In its standardized form, the normal distributionA) cannot be used to approximate discrete probability distributions.B) has an area equal to 0.5.C) has a mean of 0 and a standard deviation of 1.D) has a mean of 1 and a variance of 0.28) For a population frame containing N = 1,007 individuals, what code number should you assign to the first person onthe list in order to use a table of random number s?A) 0 B) 01 C) 0001 D) 129) You know that the probability of a randomly selected student will cheat on an exam is 1%. You also know that theprobability of a randomly selected student will cheat on an exam knowing that his/her fellow classm ate is cheating on theexam is also 1%. Which of the following is true about the event of "the randomly selected student cheating on an exam"and "his/her classmate is cheating on the exam"?A) They are mutually exclusive. B) They are statistically independent.C) They are collectively exhaustive.D) None of the above.30) If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows anormal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the probability that a randomlyselected college student will take between 2 and 4.5 minutes to find a parking spot in the library parking lot.A) 0.4938B) 0.0919C) 0.7745D) 0.2255

 

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