asu ecn 221 exam 1 study guide questions with detailed correct answers

interquartile range - correct answers which of the following is a measure of dispersion? always equal to zero - correct answers the sum of deviations of the individual data elements from their mean is_____. at least zero - correct answers the value of the sum of the squared deviations form the mean, i.e., summation(x-xbar)^2 must always be______. the difference between the third and first quartiles - correct answers the interquartile range is_________. P(A ∪ B) = P(A) + P(B) - correct answers events A and B are mutually exclusive. which of the following statements is also true? 0.07615 (multiply the two numbers) - correct answers if A and B are independent events with P(A)=0.301 and P(B)=0.253, then P(A ∩ B)=_________ posterior probabilites - correct answers revised probabilities of events based on additional information are________. cannot be both mutually exclusive and independent - correct answers two events with nonzero probabilities_________. 0.059886 - correct answers Five Cs Bank issues credit cards to its customers. In the past 3.4% of the out-of-state nonfraudulent credit card transactions were made at gasoline stations and 9.2% of the out-of-state fraudulent credit card transactions were made at gasoline stations. Based on historical transactions 97.7% of out-of-state credit card transactions are legitimate while the rest of its out-of-state credit card transactions are fraudulent. An out-of-state credit card transaction took place at a gasoline station, what is the probability the transaction is fraudulent? 0.284848 - correct answers What is the probability that a customer is in the 18-30 age group? Product Preference age 18-30 age 31-45 age 46+ Strawberry 33 36 32 Blueberry 14 23 27 0.728938 - correct answers what is the probability that a customer is in tempe or prefers chocolate or both? Product Preference Flagstaff Tempe Tucson Vanilla 43 71 31 Chocolate 35 61 32 0.320856 - correct answers what is the probability that a customer is in the 46+ age group?Product Preference age 18-30 age 31-45 age 46+ Strawberry 53 27 33 Blueberry 22 25 27 0.0771 - correct answers The random variable x is the number of occurrences of an event over an interval of 10 minutes. It can be assumed the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in 10 minutes is 5.3. Refer to exhibit 5-11. the probability there are 8 more occurrences in 10 minutes is_________. 0.181818 - correct answers What is P(YES warranty | PAID CASH)? Warranty purchase PAID CASH STORE CREDIT ACCT CREDIT CARD YES 2 12 53 NO 9 20 71 the number of female students out of 8 - correct answers the student body of a large university consists of 61% female students. a random sample of 8 students is selected. what is the random variable in this experiment? none of the answers is correct - correct answers the probability of no breakdowns in a month is____________. # of breakdowns probability 0 .12 1 .38 2 .25 3 .18 4 .07 continuous - correct answers experimental outcomes that are based on measurement scales such as time, weight, and distance can be described by ___________________ random variables 0.11216 - correct answers in a binomial experiment, the probability of success is 0.46. what is the probability of 7 successes in 20 trials? .0768 - correct answers Sandy's Pet Center grooms large and small dogs. it takes Sandy 20 minutes to groom a small dog and 70 minutes to groom a large dog. large dogs account for 40% of Sandy's business. Sandy has 5 appointments tomorrow. what is the probability that 4 appointments tomorrow are for large dogs? 0.060727 - correct answers a life insurance company has determined that each week an average of 9 claims are filed in its Denver branch. what is the probability that exactly 5 claims will be filed during the next week? 0.230211 - correct answers a production process produces 5.9% defective parts. a sample of 21 parts from the production process is selected. what is the probability that the sample contains exactly 2 defective parts? variance - correct answers the descriptive measure NOT measured in the same units as the original data is the_____________. -1 and +1 - correct answers the correlation coefficient ranges from which 2 values? population parameter - correct answers a numerical measure, such as a mean, computed from a population is known as__________. AVERAGE - correct answers excel's ___________ function can be used to compute the mean. all the sample points belonging to A or B or both - correct answers the union of events A and B is the event containing ___________. 8 - correct answers three applications to a local university are checked to determine whether each applicant is male or female. the number of sample points in this experiment is _________. 80% - correct answers 20% of people at a company picnic got food poisoning. what percent of people at the picnic did NOT get food poisoning? they have no sample points in common - correct answers two events are mutually exclusive if______. 0.32995 - correct answers Performance Boating gets 52% of its sparks plugs from Sparks Unlimited and the rest of its spark plugs from United Engines. In the past 5% of the spark plugs from Sparks Unlimited are defective and 11% of the spark plugs from United Engines are defective. A spark plug is defective, what is the probability it came from Sparks Unlimited? 0.26457 - correct answers Precision Manufacturing gets 41% of its valves from Hammond Inc. and the rest of its valves from SINGER. Historically 0.12% of the valves it gets from Hammond Inc. are defective and 0.03% of the valves it gets from SINGER are defective. A valve is found to be defective, what is the probability the valve came from SINGER? 0.117224 - correct answers the student body of a large university consists of 61% female students. a random sample of 8 students is selected. what is the probability among the students in the sample at least 7 are female? discrete random variable - correct answers a marketing manager instructs his team to make 80 telephone calls to attempt to sell an insurance policy. the random variable in this experiment is the number of sales made. this random variable is a ______________. poisson distribution - correct answers when dealing with the number of occurrences of an even over a specified interval of time or space and when the occurrence or nonoccurrence in any interval is independent of the occurrence or nonoccurrence in any other interval, the appropriate probability distribution is a _______________. the number of female voters out of 5 - correct answers 40% of all registered voters in the national election are female. a random sample of 5 voters is selected. what is the random variable in this experiment? individual outcome of an experiment - correct answers a sample point refers to a(n)__________. must always be equal to 0 - correct answers the probability of the intersection of two mutually exclusive events___________. .24 - correct answers if P(A|B)=.3 and P(B)=.8, then_____. is the average value for the random variable over many repeats of the experiment - correct answers the expected value of a discrete random variable___________. continuous random variable - correct answers highway patrol officers measure the speed of automobiles on a highway using radar equipment. the random variable in this experiment is speed, measured in mph. this random variable is a _____________. none of the following - correct answers which of the following is(are) required condition(s) for a discrete probability function? individual outcome of experiment - correct answers sample point measures_______. gender, marital status - correct answers qualititative numeric values - correct answers quantitative (100-p), top 10% is 90th percentile - correct answers percentile summarizing the data and their distribution - correct answers what are quartiles used for? max-min - correct answers range max-min - correct answers range square root of variance - correct answers standard deviation measures how far data is spread out - correct answers variance unusually small number value with a z-score -3 or +3 might be an outlier - correct answers outlier indicated the direction of a linear relationship between two variables -positive is positive -negative is negative - correct answers covariance measure of linear association - correct answers correlation -1 is a strong negative relationship. +1 is a strong positive relationship. closer to 0, the weaker - correct answers correlation coefficient assigning probabilities based on assumption of equally likely outcomes - correct answers classical probability assigning probabilities based on experimentation or historical data - correct answers relative probability assigning probabilities based on judgment - correct answers subjective probability collection of sample points - correct answers event probability Q3-Q1 - correct answers interquartile range - correct answers interquartile range