QMB 3200 Test 1 Questions And Answers With Verified Solutions

What is the z score formula? - CORRECT ANSWER-(the observation - mean) / standard deviation What does a z score tell us? - CORRECT ANSWER-how many standard deviations a value of from the mean How do you find the range? - CORRECT ANSWER-biggest value minus smallest value What is the formula used in excel to find the range? - CORRECT ANSWER-=max(array) - min (array) If a data set has an odd number of observations, the median a. Cannot be determined b. is the value of the middle item when all items are arranged in ascending order c. is the average value of the two middle items when all items are arranged in ascending order. d. must be equal to the mean - CORRECT ANSWER-b. is the value of the middle item when all items are arranged in ascending order Which of the following represents the data point that occurs most frequently in a set of observations? a. Mean b. Mode c. All of these choices are correct d. Median - CORRECT ANSWER-b. Mode The median of a data set is represented by the: a. 50th percentile b. 75th percentile c. 100th percentile d. 25th percentile - CORRECT ANSWER-a. 50th percentile Which of the following is a possible reason for an outlier in a data set? a. A mistake was made while taking a measurement or entering it into the computer b. The individual in question belongs to a different group than the bulk of individuals measured c. The outlier is a legitimate data value and represents natural variability for the group and variables measured d. All of these choices are possible reasons for an outlier - CORRECT ANSWER-d. All of these choices are possible reasons for an outlier The following is the frequency distribution for the ages of a sample of senior citizens who attend a local bingo night. What is the standard deviation for this data set? Age / Frequency 60-61 / 15 65-69 / 8 70-74 / 11 75-79 / 6 Total: 40 a. 47.8 b. 4.19 c. 17.54 d. 68 - CORRECT ANSWER-b. 4.19 A table or rule that assigns probabilities to the possible values of a discrete random variable X is called the: a. probability function b. expected value c. conditional probability d. five-number summary - CORRECT ANSWER-a. probability function Which of the following is a characteristic of a binomial experiment? a. The trials are dependent b. Each trial results in one of three outcomes c. The probability of a failure, 1 - p remains constant from trial to trial d. The experiment consists of n different trials - CORRECT ANSWER-c. The probability of a failure, 1 - p remains constant from trial to trial A random variable: a. can be classified as being continuous b. can be classified as being discrete c. is a numerical description of the outcome of an experiment d. all of these choices are correct - CORRECT ANSWER-d. all of these choices are correct The number of trees on a one-acre parcel of property is what type of variable? a. categorical b. qualitative c. continuous d. discrete - CORRECT ANSWER-d. discrete An experiment consists of four possible outcomes with P(E1) =.25, P(E2) =.10, and P(E3) =.20. The probability of outcome E4 is: a. .50 b. 1 c. .55 d. .45 - CORRECT ANSWER-d. .45 The method used to assign probabilities when the results of experimentation or historical data are used to assign probability values is referred to as the: a. classical method b. subjective method c. relative frequency method d. posterior method - CORRECT ANSWER-c. relative frequency method An experiment consists of surveying 50 customers at a local car dealership. The random variable in this experiment is the number of minutes a customer spends at the dealership. This random variable is a: a. continuous random variable b. discrete random variable c. complex random variable d. none of these choices - CORRECT ANSWER-a. continuous random variable An event is: a. a collection of sample points b. a collection of equally likely events c. a collection of sample means d. a collection of sample points that are all equal - CORRECT ANSWER-a. a collection of sample points Which of the following is a continuous random variable? a. the number of houses for sale in a city b. the number of correct answers on a multiple choice test c. the number of goals scored in a hockey game d. the heights of children in a preschool - CORRECT ANSWER-d. the heights of children in a preschool In a survey of customers at a music store the age of the person was recorded and is shown below. What is the probability that a randomly chosen customer is between the age of 15 and 19? Age / Number of Customers 15-19 / 25 20-14 / 42 25-29 / 39 30+ / 19 a. .25 b. .04 c. .42 d. .20 - CORRECT ANSWER-d. .20 Which of the following defines the event that an even number appears on the upper face when a die is rolled? a. E = {1, 2, 3, 4, 5, 6} b. E = {2, 4, 6} c. E = {1, 3, 5} d. E = {2, 6} - CORRECT ANSWER-b. E = {2, 4, 6} Of the passengers on a 757 airliner, 40% are female. A random sample of 25 passengers is selected. What is the expected number of female passengers in the sample? a. 6 b. 10 c. 25 d. 40 - CORRECT ANSWER-b. 10 Which of the following could represent a discrete uniform probability function? a. f(x) = 4^x b. f(x) = 5 n where n is the number of values the random variable can assume c. f(x) = 1/6 d. f(x) = 6/5 - CORRECT ANSWER-c. f(x) = 1/6 If a random variable can assume one of five outcomes and the distribution is uniform, what is the probability function for this random variable? a. f(x) = 1/5x b. f(x) = 5 c. f(x) = .20 d. f(x) = x^5 - CORRECT ANSWER-c. f(x) = .20 Which of the following is NOT true when assigning probabilities to each of n experimental outcomes in a sample space? a. 0 <_ P(Ei) <_ 1 b. P(E1) + P(E2) + ... + P(En) = 0 c. P(S) = 1 where S is the sample space d. P(E1) + P(E2) + ... + P(En) = 1 - CORRECT ANSWER-b. P(E1) + P(E2) + ... + P(En) = 0 A binomial experiment is conducted in which 30 dishwashers are randomly selected from a production plant and tested to determine whether or not they function properly. Any specific dishwasher will work properly with a probability of p = .98. What is the random variable in this experiment? a. the 30 dishwashers b. one dishwasher and whether it works properly c. the probability that the dishwasher works properly d. the number that works properly form the 30 selected - CORRECT ANSWER-d. the number that works properly form the 30 selected