OMIS 3200 Final Exam
What are the four levels of measurement?
Nominal, ordinal, interval, and ratio.
Contingency table
Summarizes the outcome of two categorical variables jointly.
What is the difference between and bar chart and Pareto diagram?
A Pareto diagram is a vertical bar chart that shows categories in descending order of frequency.
Frequency distribution
A summary/frequency table in which the data are arranged into numerically ordered intervals called bins.
Which of the following statements is false? A) Increasing the sample size will always reduce the size of the sampling error when the sample mean is used to estimate the population mean. B) Increasing the sample size will reduce the potential for extreme sampling error. C) Sampling error can occur when x differs from μ due to the fact that the sample was not a perfect reflection of the population. D) There is no way to prevent sampling error short of taking a census of the entire population.
A) Increasing the sample size will always reduce the size of the sampling error when the sample mean is used to estimate the population mean.
An Internet service provider has the capability of tracking the time that each of its customers spends connected to the Internet during a month. These data would constitute: A) a population. B) a convenience sample. C) a cluster sample. D) a simple random sample.
A) a population.
An identification of police officers by rank would represent a(n) ________ level of measurement. A) ordinal B) interval C) ratio D) nominative
A) ordinal
A Wall Street Journal poll asked 2,150 adults in the U.S. a series of questions to find out their view on the U.S. economy. The 2,150 adults make up: A) the sample. B) the primary data source. C) the secondary data source. D) the population.
A) the sample.
Descriptive statistics
Aims to collect data, summarize them, and then describe the data in a meaningful way to the decision-makers.
At the end of their final exam, 550 students answered an additional question in which they rated their instructor's teaching effectiveness, with the following results. What proportion of the students who rated their instructor as very or somewhat effective received a B or better in the class? A) 0.345 B) 0.482 C) 0.898 D) 0.254 E) 0.644
C) 0.898
A sales rep for a national clothing company makes 4 calls per day. Based on historical records, the following probability distribution describes the number of successful calls each day. The expected number of successful sales calls per day is: A) 2.00 B) 1.15 C) 1.90 D) 2.50
C) 1.90
At a meeting of information systems officers for regional offices of a national company, a survey was taken to determine the number of employees the officers supervise in the operation of their departments, where X is the number of employees overseen by each information systems officer. Across all of the regional offices, how many total employees were supervised by those surveyed? A) 15 B) 40 C) 127 D) 200
C) 127
The monthly electrical utility bills of all customers for the Far East Power and Light Company are known to be distributed as a normal distribution with a mean equal to $87.00 a month and a standard deviation of $36.00. If a statistical sample of n = 100 customers is selected at random, what is the probability that the mean bill for those sampled will exceed $75.00? A) -0.33 B) Approximately 0.63 C) About 1.00 D) 3.33
C) About 1.00
________ and ________ are used to describe qualitative (categorical) data. A) Pie charts ; histograms B) Scatter plots ; histograms C) Box plots ; bar charts D) Bar charts ; pie charts
C) Box plots ; bar charts
What is the most appropriate measure to describe the center of the data shown by the below histogram? A) Mean B) Range C) Median D) Mode
C) Median
The change in the daily price of a stock is what type of variable? A) Random B) Ordinal C) Quantitative D) Qualitative
C) Quantitative
________ is the science of using a sample to make generalizations about the important aspects of a population. A) Random sample B) Descriptive statistics C) Statistical inference D) Time series analysis
C) Statistical inference
An event is: A) more frequently found in business than in other disciplines. B) similar to an experiment but not controlled by the decision maker. C) a collection of elementary events. D) the list of possible outcomes that can occur from a selection or decision.
C) a collection of elementary events.
If either event A or event B must occur, then events A and B are said to be: A) mutually exclusive. B) independent. C) collectively exhaustive. D) none of these options.
C) collectively exhaustive.
The estimation of the population average family expenditure on food based on the sample average expenditure of 1,000 families is an example of: A) a parameter. B) a statistic. C) descriptive statistics. D) inferential statistics.
C) descriptive statistics.
If two events are independent, then: A) the sum of their probabilities must be equal to one. B) they must be mutually exclusive. C) none of these options. D) their intersection must be zero.
C) none of these options.
The Polson Pole and Fence Company recently did a quality check on the length of fence posts. To do this, each of the 400 posts in inventory was numbered. Numbers from 1 to 400 were placed in a bowl. Twenty numbers were selected from the bowl without looking. These 20 poles were the ones selected for the study. This type of sampling is called: A) convenience sampling. B) cluster sampling. C) simple random sampling. D) nonstatistical.
C) simple random sampling.
A company believes that there will be a 50% chance of making a profit of $1000, a 30% chance of making a profit of $1500, and a 20% chance of making a profit of $2000. What is the expected profit? A) $1000 B) $300 C) $2000 D) $1350 E) $4500
D) $1350
Assuming that the change in daily closing prices for stocks on the New York Stock Exchange is a random variable that is normally distributed with a mean of $.35 and a standard deviation of $.33. Based on this information, what is the probability that a randomly selected stock will close up $.75 or more? A) 0.7100 B) 0.3869 C) 0.8869 D) 0.1131
D) 0.1131
The employees of a company were surveyed on questions regarding their educational background (college degree or no 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 is single or has a college degree is: A) 0.10 B) 0.25 C) 0.667 D) 0.733
D) 0.733
A company has 2 machines that produce widgets. An older machine produces 23% defective widgets, while the new machine produces only 8% defective widgets. In addition, the new machine produces 3 times as many widgets as the older machine does. Given that a widget was produced by the new machine, what is the probability it is not defective? A) 0.06 B) 0.50 C) 0.94 D) 0.92
D) 0.92
If two events are collectively exhaustive, what is the probability that one or the other occurs? A) Cannot be determined from the information given. B) 0 C) 0.50 D) 1.00
D) 1.00
The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day. Based on this distribution, the expected number of accidents in a given day is: A) 0.30 B) 2.00 C) 2.50 D) 1.65
D) 1.65
In a statistics class, 10 scores were randomly selected with the following results: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What is the IQR? A) 12.00 B) 5.25 C) 11.00 D) 10 E) 5.00
D) 10
The local amusement park was interested in the average wait time at their most popular roller coaster at the peak park time (2 p.m.). They selected 13 patrons and had them get in line between 2 and 3 p.m. Each was given a stopwatch to record the time they spent in line. The times recorded were as follows (in minutes). 118, 124, 108, 116, 99, 120, 148, 118, 119, 121, 45, 130, 118. What is the 65th percentile? A) 130 B) 99 C) 45 D) 120 E) 112
D) 120
At a meeting of information systems officers for regional offices of a national company, a survey was taken to determine the number of employees the officers supervise in the operation of their departments, where X is the number of employees overseen by each information systems officer. How many regional officers are represented in the survey results? A) 15 B) 5 C) 11 D) 40
D) 40
If events A and B are mutually exclusive and collectively exhaustive, what is the probability that event A occurs? A) 0 B) 0.50 C) 1.00 D) Cannot be determined from the information given.
D) Cannot be determined from the information given.
If two events are collectively exhaustive, what is the probability that both occur at the same time? A) 0 B) 0.50 C) 1.00 D) Cannot be determined from the information given.
D) Cannot be determined from the information given.
Which one of the following is not statistical sampling? A) Simple random sample B) Stratified random sampling C) Cluster sampling D) Convenient sampling
D) Convenient sampling
In a standard normal distribution, the probability P(-1.00< Z < 1.20) is the same as: A) P(1<Z<1.20) - 2*P(0<Z<1.00) B) 2*P(1<Z<1.20) - P(0<Z<1.00) C) P(1<Z<1.20) - P(0<Z<1.00) D) P(1<Z<1.20) + 2*P(0<Z<1.00)
D) P(1<Z<1.20) + 2*P(0<Z<1.00)
A company collected the ages from a random sample of its middle managers, with the resulting frequency distribution shown below. What would be the approximate shape of the relative frequency histogram? A) Symmetrical B) Uniform C) Multiple peaks D) Skewed to the left E) Skewed to the right
D) Skewed to the left
Interval level of measurement
For data recorded at the interval level of measurement, the interval or the distance between values is meaningful. The interval level of measurement is based on a scale with a known unit of measurement (e.g. Fahrenheit temperature scale, dress sizes).
Business statistics
The science that transforms data into useful information and insights for decision-makers.
True or false: the median is always the 50th percentile.
True.
Predictive statistics
Uses past data to predict the future or study the impact of on variable on another.
Suppose that it is believed that investor returns on equity investments at a particular brokerage house are normally distributed with a mean of 9 percent and a standard deviation equal to 3.2 percent. What percent of investors at this brokerage hour earned at least 5 percent? A) 89.44 percent B) 39.44 percent C) 100 percent D) 10.56 percent
A) 89.44 percent
Assuming that the change in daily closing prices for stocks on the New York Stock Exchange is a random variable that is normally distributed with a mean of $0.35 and a standard deviation of $0.33. Based on this information, what is the probability that a randomly selected stock will be lower by $0.40 or more? A) 2.27 B) 0.4884 C) 0.0116 D) 0.9884
C) 0.0116
The manager at a local movie theater has collected data for a long period of time and has concluded that the revenue from concession sales during the first show each evening is normally distributed with a mean equal to $336.25 and a standard deviation equal to $80. Based on this information, what are the chances that the revenue on the first show will be between $300 and $500? A) Approximately 0.6534 B) Approximately 0.4798 C) 0.1736 D) About 0.3062
A) Approximately 0.6534
If the mean, median, and mode for a given population all equal 25, then we know that the shape of the distribution of the population is ________. A) skewed to the left B) symmetrical C) skewed to the right D) bimodal
B) symmetrical
If two events are mutually exclusive, what is the probability that both occur at the same time? A) 1.00 B) 0.50 C) 0 D) Cannot be determined from the information given.
C) 0
In a statistics class, 10 scores were randomly selected with the following results: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What is the first quartile? A) 67.0 B) 73.85 C) 77.0 D) 67.3 E) 65.9
A) 67.0
In a statistics class, 10 scores were randomly selected, with the following results: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What is the 90th percentile? A) 77 B) 73 C) 67 D) 65.9 E) 74
A) 77
The option to buy extended warranties is commonplace with most electronics purchases. But does the type of purchase affect a consumer's willingness to pay extra for an extended warranty? Data for 420 consumers who purchased digital cameras and laptop computers from a leading electronics retailer are summarized in the table. The probability that a consumer purchases a digital camera and an extended warranty is: A) .07 B) .17 C) .58 D) .42 E) .83
A) .07
The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day. Based on this probability distribution, the standard deviation in the number of accidents per day is: A) .28 B) 2.0 C) 1.63 D) 2.65
A) .28
A company collected the ages from a random sample of its middle managers, with the resulting frequency distribution shown below. What is the relative frequency for the largest interval (the one with most managers)? A) .283 B) .226 C) .132 D) .288 E) .231
A) .283
A recent survey of local cell phone retailers showed that of all cell phones sold last month, 64% had a camera, 28% had a music player and 22% had both. The probability that a cell phone sold last month did not have either a camera or a music player is: A) .30 B) .70 C) .08 D) .22 E) .92
A) .30
A recent survey of local cell phone retailers showed that of all cell phones sold last month, 64% had a camera, 28% had a music player and 22% had both. The probability that a cell phone sold last month had a camera or a music player (not both) is: A) .70 B) .30 C) .92 D) .22 E) .08
A) .70
The probability that house sales will increase in the next 6 months is estimated to be 0.25. The probability that the interest rates on housing loans will go up in the same period is estimated to be 0.74. The probability that house sales or interest rates will go up during the next 6 months is estimated to be 0.89. The probability that both house sales and interest rates will increase during the next 6 months is: A) 0.10 B) 0.185 C) 0.705 D) 0.90
A) 0.10
The probability that house sales will increase in the next 6 months is estimated to be 0.25. The probability that the interest rates on housing loans will go up in the same period is estimated to be 0.74. The probability that house sales or interest rates will go up during the next 6 months is estimated to be 0.89. The probability that neither house sales nor interest rates will increase during the next 6 months is: A) 0.11 B) 0.195 C) 0.89 D) 0.90
A) 0.11
The probability that a new advertising campaign will increase sales is assessed as being 0.80. The probability that the cost of developing the new ad campaign can be kept within the original budget allocation is 0.40. Assuming that the two events are independent, the probability that neither the cost is kept within budget nor the campaign will increase sales is: A) 0.12 B) 0.32 C) 0.88 D) 0.68
A) 0.12
The State Department of Weights and Measures is responsible for making sure that commercial weighing and measuring devices, such as scales, are accurate so customers and businesses are not cheated. Periodically, employees of the department go to businesses and test their scales. For example, dairy bottles of milk in 1-gallon containers. Suppose that if the filling process is working correctly, the mean volume of all gallon containers is 1.00 gallons with a standard deviation equal to 0.10 gallons. Based on this information, if the department employee selects a random sample of n = 9 containers, what is the probability that the mean volume for the sample will be greater than 1.01 gallons? A) 0.3821 B) 0.1179 C) 0.6179 D) 0.2358
A) 0.3821
The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day. The probability of having less than two accidents on a given day is: A) 0.45 B) 0.30 C) 0.75 D) 0.25
A) 0.45
According to a survey of American households, the probability that the residents own 2 cars if their annual household income is over $50,000 is 80%. Of the households surveyed, 60% had incomes over $50,000 and 70% had 2 cars. The probability that the residents of a household own 2 cars and have an income over $50,000 a year is: A) 0.48 B) 0.22 C) 0.12 D) 0.18
A) 0.48
A sales rep for a national clothing company makes 4 calls per day. Based on historical records, the following probability distribution describes the number of successful calls each day. Based on the information provided, what is the probability of having at least two successful calls in one day? A) 0.60 B) 0.20 C) 0.30 D) 0.10
A) 0.60
The local amusement park was interested in the average wait time at their most popular roller coaster at the peak park time (2 p.m.). They selected 13 patrons and had them get in line between 2 and 3 p.m. Each was given a stopwatch to record the time they spent in line. The times recorded were as follows (in minutes). 118, 124, 108, 116, 99, 120, 148, 118, 119, 121, 45, 130, 118. What are the lower and upper limits (inner fence)? A) 108.5, 128.5 B) 15.75, 31.50 C) 80.5, 154.00 D) 127.75, 138.25 E) 143.50, 154.00
A) 108.5, 128.5
822 customers were randomly selected from those who had recently bought a book over the Internet. The chart below shows the breakdown of the classification of the book type. What percentage of the books purchased were either mystery or science fiction/fantasy? A) 36.50 B) 17.88 C) 18.61 D) 22.99 E) 24.33
A) 36.50
A company believes that there will be a 50% chance of making a profit of $1000, a 30% chance of making a profit of $1500, and a 20% chance of making a profit of $2000. Find the standard deviation for the company's profit? A) 390.51 B) 152 500 C) 350 D) 18.71 E) 1350
A) 390.51
The option to buy extended warranties is commonplace with most electronics purchases. But does the type of purchase affect a consumer's willingness to pay extra for an extended warranty? Data for 420 consumers who purchased digital cameras and laptop computers from a leading electronics retailer are summarized in the table. The probability that a consumer purchases an extended warranty given that he/she has purchased a digital camera is: A) .07 B) .42 C) .58 D) .17 E) .83
B) .42
The managers of a local golf course have recently conducted a study of the types of golf balls used by golfers based on handicap. A joint frequency table for the 100 golfers covered in the survey is shown below. Based on these data, the probability that a player will use a Strata golf ball is: A) 0.15 B) 0.20 C) 0.18 D) None of these options.
B) 0.20
According to a survey of American households, the probability that the residents own 2 cars if their annual household income is over $50,000 is 80%. Of the households surveyed, 60% had incomes over $50,000 and 70% had 2 cars. The probability that the residents do not own 2 cars if their annual household income is not over $50,000 is: A) 0.70 B) 0.45 C) 0.18 D) 0.12
B) 0.45
A local electronics retailer recently conducted a study on purchasers of large-screen televisions. The study recorded the type of television and the credit account balance of the customer at the time of purchase. They obtained the following results. What percentage of purchases were plasma televisions by customers with the smallest credit balances? A) 56.30 B) 19.60 C) 39.20 D) 34.80 E) 50.00
B) 19.60
In a statistics class, 10 scores were randomly selected with the following results: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What are the lower and upper limits? A) 67, 77 B) 52, 92 C) 37, 107 D) 47, 97 E) 57, 87
B) 52, 92
In a statistics class, the following 10 scores were randomly selected: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What is the mean? A) 72.0 B) 71.5 C) 73.0 D) 71.0 E) 77.0
B) 71.5
Consider the following two probability distributions. Which of the following is an accurate statement regarding these two distributions? A) Both distributions are uniform. B) Distribution A has a higher variance. C) Both distributions are positively skewed. D) Distribution B has a higher variance.
B) Distribution A has a higher variance.
Which of the following is not a characteristic of the normal distribution? A) Symmetric B) Equal probabilities at all values of x C) Bell-shaped D) Mean=median=mode
B) Equal probabilities at all values of x
Which one of the following graphical tools is used with quantitative data? A) Bar chart B) Histogram C) Pareto chart D) Pie chart
B) Histogram
Which of the following statements is incorrect? A) The standard deviation of a discrete probability distribution measures the average deviation of the random variable from the mean. B) The mean of the probability distribution is equal to the square root of the variance. C) The expected value of a discrete probability distribution is the long-run average value assuming the experiment will be repeated many times. D) The distribution is considered uniform if all the probabilities are equal.
B) The mean of the probability distribution is equal to the square root of the variance.
A Wall Street Journal poll asked 2,150 adults in the U.S. a series of questions to find out their views on the U.S. economy. The population of interest is: A) all the females living in the U.S. when the poll was taken. B) all the adults living in the U.S. when the poll was taken. C) all the males living in the U.S. when the poll was taken. D) all the people living in the U.S. when the poll was taken.
B) all the adults living in the U.S. when the poll was taken.
A measurement located outside the upper limits of a box-and-whiskers display is ________. A) always the largest value in the data set B) an outlier C) within the lower limits D) always in the first quartile
B) an outlier
If a population distribution is skewed to the right, then, given a random sample from that population, one would expect that the ________. A) median would be equal to the mean B) median would be less than the mean C) mode would be equal to the mean D) median would be greater than the mean
B) median would be less than the mean
A company has determined that the mean number of days it takes to collect on its accounts receivable is 36 with a standard deviation of 11 days. The company plans to select a random sample of n = 12 accounts and compute the sample mean. Which of the following statements holds true in this situation? A) There is no way to determine what the mean of the sampling distribution is without knowing the specific shape of the population. B) The sampling distribution will have the same distribution as the population, provided that the population is not normally distributed. C) The sampling error will be larger than if they had sampled n = 64 accounts. D) The sampling distribution may actually be approximately normally distributed depending on what the population distribution is.
D) The sampling distribution may actually be approximately normally distributed depending on what the population distribution is.
When an accounting auditor randomly selects 20 accounts from all the accounts to check for accuracy, she has selected: A) a personal observation. B) a convenience sample. C) a census. D) a sample from the population.
D) a sample from the population.
The collection of all possible events is called: A) the null set. B) a simple probability. C) a joint probability. D) a sample space.
D) a sample space.
All the events in the sample space that are not part of the specified event are called: A) simple events. B) joint events. C) the sample space. D) the complement of the event.
D) the complement of the event.
Nominal level of measurement
Data recorded at the nominal level of measurement is represented as labels or names. They have no order and do not permit any mathematical operation (e.g. colors, genders, names)
Ordinal level of measurement
Data recorded at the ordinal level of measurement is based on a relative ranking or rating of items in terms of a defined attribute or qualitative variable (e.g. student ratings of professors from poor, average, good, and superior).
Ratio level of measurement
Data recorded at the ratio level of measurement are based on a scale with a known unit of measurement and a meaningful interpretation of zero on the scale (e.g. wages, changes in stock prices, height).
Scatter plot
Describes the relationship of two numerical variables (e.g. sales and advertising spending).
Inferential statistics
Draws conclusions about a population from a sample.
A recent survey of local cell phone retailers showed that of all cell phones sold last month, 64% had a camera, 28% had a music player and 22% had both. Which of the following statements about cell phones sold last month is true? A) Having a camera and having a music player are mutually exclusive events. B) The intersection of having a camera and having a music player is zero. C) Having a camera and having a music player are independent events. D) Having a camera and having a music player are disjoint events. E )Having a camera and having a music player are not mutually exclusive events.
E )Having a camera and having a music player are not mutually exclusive events.
The option to buy extended warranties is commonplace with most electronics purchases. But does the type of purchase affect a consumer's willingness to pay extra for an extended warranty? Data for 420 consumers who purchased digital cameras and laptop computers from a leading electronics retailer are summarized in the table. The probability that a consumer does not purchase an extended warranty is: A) .42 B) .83 C) .17 D) .07 E) .58
E) .58
In a statistics class, 10 scores were randomly selected with the following results (mean = 71.5): 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What is the range? A) 144.00 B) 22.72 C) 516.20 D) 4.77 E) 12.00
E) 12.00
During its grand opening week, Stickler's bicycle shop offers a "wheel of discount savings." After customers select the items they wish to purchase, they spin the wheel to determine the discount they will receive. The wheel is divided into 12 slices. Six slices are red and award a 10% discount, three slices are white and award a 20% discount, and two slices are blue and award a 40% discount. The remaining slice is gold and awards a 100% discount! The probability that a customer gets at least a 40% discount is: A) 9/12 B) 10/12 C) .0625 D) 2/12 E) 3/12
E) 3/12
The local amusement park was interested in the average wait time at their most popular roller coaster at the peak park time (2 p.m.). They selected 13 patrons and had them get in line between 2 and 3 p.m. Each was given a stopwatch to record the time they spent in line. The times recorded were as follows (in minutes). 118, 124, 108, 116, 99, 120, 148, 118, 119, 121, 45, 130, 118. What is the IQR? A) 28 B) 7 C) 103 D) 30 E) 5
E) 5
In a statistics class, the following 10 scores were randomly selected: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What is the median? A) 73.0 B) 77.0 C) 71.0 D) 71.5 E) 72.0
E) 72.0
When developing a frequency distribution, the class (group) intervals should be ________. A) equal B) integer C) small D) large E) mutually exclusive
E) mutually exclusive
What are examples of well-known numbers (measures)?
Mean, median, mode, variance, etc.
Ogive curve
Measures the accumulated percentage of the current category plus all those categories on the left.
