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Business Analytics 1 Final Exam 2024 ||
All Questions & Answers (Graded A+)
T or F: A quantitative variable can also be referred to as a categorical variable. - ANSWER - False A(n) ________ variable is a qualitative variable such that there is no meaningful ordering or ranking of the categories. - ANSWER - nominal Measurements from a population are called - ANSWER - observations Which of the following describes the steps of the Analytic Process after we know the business problem? - ANSWER - Choose DataSourcing Method-Collect Descriptives- Make Prediction-Ask Next Question A doctor's office needs to know how many of their services are used by their patients during a one year time period. Before a patient leaves their office, a summary report includes the date, the doctor they saw, the services provided, and the total charge for each service. Which of the following datasourcing methods best describes this data collection scenario? - ANSWER - point of sale A commercial shipping company operates a large fleet of trucks. The company needs to collect data on vehicle usage including acceleration, braking, and vehicle maintenance such as fluid levels. The datasourcing method needed to collect the data for this scenario is - ANSWER - sensor T or F: Business analytics is a new field that does not use traditional statistics to analyze big data - ANSWER - false A person's telephone area code is an example of a(n) ________ variable. - ANSWER - nominal Which of the following is a quantitative variable? - ANSWER - Mileage of a car Possible qualitative data for Stitchfix to collect is a clothing size such as small, medium, and large. This is an example of __________ (ordinal, nominal, discrete, or continuous) variable. - ANSWER - ordinal A ________ variable takes on values that are numbers on the real number line. - ANSWER - quantitative T or F: An example of a qualitative variable is the mileage of a car. - ANSWER - false
A(n) ________ variable can have values that indicate into which of several categories of a population it belongs. - ANSWER - qualitative In the Analytic Process, the next step after the descriptives (descriptives is the data that has occurred up to the current point in time) have been collected, is to use the data to: - ANSWER - make predictions An identification of police officers by rank would represent a(n) ________ level of measurement. - ANSWER - ordinal T or F: In systematic sampling, the first element is randomly selected from the first (N/n) elements. - ANSWER - true Nonoverlapping groups of similar elements in a population are called - ANSWER - strata Amazon collects random reviews from their customers on the West Coast as the data they use for their nationwide marketing plan. This sample suffers from which sampling bias? - ANSWER - undercoverage When a person gives an answer that they think you want to hear or is politically correct, this is an example of which bias: - ANSWER - measurement error T or F: It is possible to use a random sample from a population to make statistical inferences about the entire population. - ANSWER - true In ________ we select elements because they are easy to sample. - ANSWER - convenience sampling T or F: A recording error is an error of observation. - ANSWER - true T or F: Convenience sampling is a type of probability sampling in which we select elements to sample because we believe they have the highest probability of responding.
- ANSWER - false StitchFix wants to make sure different specific characteristics, such as all different age groups, are represented in their sample. The appropriate sampling method they should use is: - ANSWER - stratified random sampling Examining all population measurements is called ________. - ANSWER - census When a low response bias occurs, what should you do? - ANSWER - Conduct another sample to increase the response rate T or F: A common practice in selecting a sample from a large geographic area is multistage cluster sampling. - ANSWER - true
________ occurs when some population elements are excluded from the process of selecting the sample. - ANSWER - undercoverage T or F: Stratification can at times be combined with multistage cluster sampling to develop an appropriate sample. - ANSWER - true T or F: Errors of non-observation occur when data values are recorded incorrectly. - ANSWER - false T or F: A low response rate has no effect on the validity of a survey's findings. - ANSWER - false T or F: A random sample is selected so that every element in the population has the same chance of being included in the sample. - ANSWER - true Which of the following questions would result in Response Bias? - ANSWER - Since hacking is so common, are you confident that the information you provide online is secure? T or F: When data are qualitative, the bars should never be separated by gaps. - ANSWER - false T or F: A bar chart is a graphic that can be used to depict qualitative data. - ANSWER - true Which of the following is a type of question used in survey research? - ANSWER - open-ended, multiple-choice, dichotomous T or F: The relative frequency is the frequency of a class divided by the total number of measurements. - ANSWER - true 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: Student's Rating of Instructor Student's Final Grade A B C D F Very or Somewhat Effective 190 75 20 9 1 Very or Somewhat Ineffective
What proportion of the students who rated their instructor as very or somewhat effective received a C or lower in the class? - ANSWER - 30/295=0. The number of measurements falling within a class interval is called the ________. - ANSWER - frequency ________ and ________ are used to describe qualitative (categorical) data. - ANSWER
- Bar charts, pie charts Consider the following data on distances traveled by people to visit the local amusement park and calculate the relative frequency for the shortest distance. Distance 1-8 miles 9-16 miles 17-24 miles 25-32 miles 33-40 miles Frequency 15 12 7 5 1 - ANSWER - 15/40=0. Consider the following data on distances traveled by people to visit the local amusement park and calculate the relative frequency for the distances over 24 miles. Distance 1-8 miles 9-16 miles 17-24 miles 25-32 miles 33-40 miles Frequency 15 12 7 5 1 - ANSWER - 6/40=0. The proportion of measurements in a class is called the ________ of that class. - ANSWER - relative frequency
Which of the following correlation coefficients describes the strongest relationship between two quantitative variables? - ANSWER - 0. An example of manipulating a graphical display to distort reality is ________. - ANSWER - stretching the axes Which of the following divides quantitative measurements into classes and graphs the frequency, relative frequency, or percentage frequency for each class? - ANSWER - histogram What is it called when we combine graphs (visuals) with predictive analytics? - ANSWER - Visual Analytics If a histogram has a long left or right tail, the data is described as: - ANSWER - skewed Which of the following correlation coefficient describes the weakest relationship between two quantitative variables? - ANSWER - 0. A ________ displays the frequency of each class with qualitative data and a ________ displays the frequency of each class with quantitative data. - ANSWER - bar chart, histogram Given a scatterplot, if one quantitative variable increases when the other quantitative variable variable decreases, the _____ is _______. - ANSWER - direction, negative Which of the following are included in the Key Points of Storytelling? - ANSWER - Choose the appropriate graph & tell an accurate story T or F: When looking at the shape of the distribution using a histogram, a distribution is skewed to the right when the left tail is shorter than the right tail. - ANSWER - true A ________ shows the relationship between two variables. - ANSWER - scatter plot Which of the following is a quantitative variable? - ANSWER - mileage of a car Which of the following is a categorical variable? - ANSWER - whether a person has a traffic violation An unusually large or small observation separated from the rest of the data is a(n) ________. - ANSWER - outlier An identification of police officers by rank would represent a(n) ________ level of measurement. - ANSWER - ordinal
A(n) ________ variable is a qualitative variable such that there is no meaningful ordering or ranking of the categories - ANSWER - nominal The Data Ethics principle that supports datasets can be made available to the public is:
- ANSWER - openness The Data Ethics principle that ensures a participant is aware of what data is being collected, the purpose, and how the data will be used is _________. - ANSWER - consent If Amazon wanted to ensure a customers' response to an online survey was confidential and the sampling method was unbiased, which of the following should be implemented?
- ANSWER - Identify each randomly selected customer by a random identification number The question "Do you use third-party cookies" is an example of what would be asked if a person was concerned about: - ANSWER - data ethics When a company sells your data from a datasourcing method such as clickstream, this is an example of which data ethic principle? - ANSWER - currency Which of the following is not an example of unethical statistical practices? - ANSWER - using graphs to make statistical inferences If we are concerned whether the data was collected confidentially or anonymously, this is an example of which data ethic principle? - ANSWER - privacy T or F: Using a nonrandom sample procedure in order to support a desired conclusion is an example of an unethical statistical procedure. - ANSWER - true From the video we watched in class (the link is provided in the powerpoint in module Misleading Graphs), the act of choosing a portion of the axis which leads to telling a misleading story is called: - ANSWER - cherry picking T or F: Statistical inference is the science of using a sample of measurements to make generalizations about the important aspects of a population of measurements. - ANSWER - true In a hearing test, randomly selected subjects estimate the loudness (in decibels) of a sound, and the results are (mean = 70): 68, 67, 70, 71, 68, 75, 68, 62, 80, 73, 68.What is the range? - ANSWER - 80 - 62 = 18 T or F: The population mean is the average of the population measurements - ANSWER - true
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 standard deviation? - ANSWER - square root of 22.71 = 4. All of the following are measures of central tendency except the ________. - ANSWER - range 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? - ANSWER - 72 T or F: Range is a better measure of variation than standard deviation. - ANSWER - false T or F: The median is the measure of central tendency that divides a population or sample into four equal parts. - ANSWER - false The ________ is the positive square root of the sample variance - ANSWER - sample standard deviation T or F: An analytic dashboard presents both current and historical trends of a business's key performance indicators. - ANSWER - true T or F: The median is said to be resistant to extreme values. - ANSWER - true If the mean, median, and mode for a given population are all equal and the relative frequency curve has matching tails to the right and left, then we would describe the shape of the distribution of the population as ________. - ANSWER - symmetrical If a population distribution is skewed to the right, then, given a random sample from that population, one would expect that the ________. - ANSWER - median would be less than the mean Another name for the 50th percentile is the ________. - ANSWER - median A survey of the top 10 employees in a major Midwest city found workers spent an average of 413 minutes per day on a job with standard deviation = 26.8 minutes. If the time spent on the job is approximately normal, what are the times within which approximately 68% of all workers fall? - ANSWER - [386.2,439.8] A normal population has 99.73 percent of the population measurements within ________ standard deviation(s) of the mean. - ANSWER - 3 T or F: The median is the value below which and above which approximately 50 percent of the measurements lie. - ANSWER - True
Find the z-score for an IQ test score of 118 when the mean is 100 and the standard deviation is 15. - ANSWER - (118- 100)/15 = 1. Personnel managers usually want to know where a job applicant ranked in his or her graduating class. With a grade point average of 3.83, Michelle Robinson graduated above the 93rd percentile of her graduating class. What is the percentile rank of a student whose GPA was the median GPA? - ANSWER - 50th The company financial officer was interested in the average cost of PCs that had been purchased in the past six months. She took a random sample of the price of 10 computers, with the following results.$3,250, $1,127, $2,995, $3,250, $3,445, $3,449, $1,482, $6,120, $3,009, $4,000What is the third quartile? - ANSWER - (75/100) x 10 = 7.5 --> 8 --> $3,449. The company financial officer was interested in the average cost of PCs that had been purchased in the past six months. She took a random sample of the price of 10 computers, with the following results.$3,250, $1,127, $2,995, $3,250, $3,445, $3,449, $1,482, $6,120, $3,009, $4,000What is the first quartile? - ANSWER - (25/100) x 10 = 2.5 --> 3 --> $2,995. 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 10th percentile? - ANSWER - (10/100) x 10 = 1 --> 65+66/2 --> 65. The average lateness for one of the top airline companies is 10 minutes. The variance of the lateness measure is calculated as 9. An airplane arrived 13 minutes after the stated arrival time. Calculate the z-score for the lateness of this particular airplane. - ANSWER - (13-10)/square root of 9= 1 The company financial officer was interested in the average cost of PCs that had been purchased in the past six months. She took a random sample of the price of 10 computers, with the following results.$3,250, $1,127, $2,995, $3,250, $3,445, $3,449, $1,482, $6,120, $3,009, $4,000What are the lower and upper limits of a box-and- whiskers display of this data? - ANSWER - 2314, 4130 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? - ANSWER - 10 Find the z-score for an IQ test score of 125 when the mean is 100 and the standard deviation is 15. - ANSWER - (125-100)/15=1. A measurement located outside the upper limits of a box-and-whiskers display is ________. - ANSWER - an outlier Which percentile describes the third quartile, Q3? - ANSWER - 75th
The ________ of an event is a number that measures the likelihood that an event will occur when an experiment is carried out. - ANSWER - probability The area under the curve of a valid continuous probability distribution must ________. - ANSWER - equal 1 A process of observation that has an uncertain outcome is referred to as a(n) ________. - ANSWER - experiment T or F: For a continuous distribution, P(X ≤ 100) = P(X < 100). - ANSWER - true The grade a student received on an examination was transformed to a z value, which was negative. Therefore, we know that he scored - ANSWER - below the mean A normal distribution with mean equal to zero and a standard deviation equal to one is called the ________ normal distribution. - ANSWER - standard Given that X is a normal random variable, the probability that a given value of X is below its mean is ________. - ANSWER - equal to 0. If the random variable x is normally distributed, ______ percent of all possible observed values of x will be within three standard deviations of the mean. - ANSWER - 99. The specific shape of each normal distribution is determined by its ________ and ________. - ANSWER - mean, standard deviation When a confidence interval for a population proportion is constructed for a sample size n = 30 and the value of pˆp^ = .4, the interval is based on - ANSWER - the z distribution. In a randomly selected group of 650 automobile deaths, 180 were alcohol related. Construct a 95 percent confidence interval for the true proportion of all automobile accidents caused by alcohol. - ANSWER - 180/650=0.2769 --> 0.2769 +- 1.96 x square root of ((0.2769 x 0.7231)/650)= 0.243 to 0. The relationship between the standard normal random variable, z, and normal random variable, X, is that - ANSWER - the standard normal variable z counts the number of standard deviations that the value of the normal random variable X is away from its mean. T or F: The z value tells us the number of standard deviations that a value, x, is from the mean. - ANSWER - true T or F: If the random variable, x, is normally distributed, 68.26 percent of all possible observed values of x will be within two standard deviations of the mean. - ANSWER - false
As the margin of error decreases, the width of the confidence interval ________. - ANSWER - decreases As the sample size n increases, the width of the confidence interval ________. - ANSWER - decreases
