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NARRBEGIN: SA_107_111 Suppose that the number of customers arriving each hour at the only checkout counter at a local convenience store is approximately Poisson distributed with an expected arrival rate of 30 customers per hour. Let X represent the number […]

In order to generate random numbers in Excel from a discrete distribution with a finite number of possible values and corresponding probabilities, we can use a. only the RAND function b. only the VLOOKUP function c. only the VLOOKDOWN function […]

Three important themes run through this book: data analysis, decision-making, and dealing with uncertainty. NARRBEGIN: SA_57_64 Amanda is a recent college graduate, and has just started her first job. She would like to know if she saves $5,000 per year […]

NARRBEGIN: SA_113_116 A construction company is preparing for a nine-month project, and will need to develop a staffing plan. The company can assign up to 30 of its own full-time employees to the project, and will hire short-term contract employees […]

Potential sample members, called sampling units, are: a. people b. companies c. households d. All of these options Which of the following functions is not appropriate in cases where we run a single simulation? a. RISKMIN b. RISKMAX c. RISKPERCENTILE […]

NARRBEGIN: SA_104_112 Mrs. Rich has just bought a new $30,000 car. As a reasonably safe driver, she believes that there is only a 5% chance of being in an accident in the forthcoming year. If she is involved in an […]

A sport preference poll yielded the following data for men and women. Use the 5% significance level and test to determine if sport preference and gender are independent. NARRBEGIN: SA_97_101 A customer has approached a local credit union for a […]

NARRBEGIN: SA_112_113 Adam Enterprises manufactures two products. Each product can be produced on either of two machines. The time (in hours) required to make each product on each machine is shown below: Each month, 500 hours of time are available […]

Which of the following is true with regard to a good decision? a. It ensures that good outcomes will be obtained b. It accounts for unlucky outcomes c. It should be independent of the sequencing of uncertainties and decisions d. […]

In a transportation problem, if it costs $4 per item to ship up to 200 items between cities, and $2 per item for each additional item, the proportionality assumption of LP is satisfied. Expressed in percentiles, the interquartile range is […]

NARRBEGIN: SA_80_83 A marketing research consultant hired by Coca-Cola is interested in determining if the proportion of customers who prefer Coke to other brands is over 50%. A random sample of 200 consumers was selected from the market under investigation, […]

The test statistic in a hypothesis test for a population proportion is a. t-value calculated from the sample b. z-value calculated from the sample c. F-value calculated from the sample d. the sample proportion NARRBEGIN: SA_100_102 A new online auction […]

If we draw a straight line through the points in a scatterplot and most of the points fall close to the line, there is a strong positive linear relationship between the two variables. The expected value of sample information (EVSI) […]

If the partial F test indicates that a group of variables is significant, it also implies that each variable in the group is significant. NARRBEGIN: SA_116_118 The table below contains 5 years of monthly data on sales (number of units […]

We should include an interaction variable in a regression model if we believe that the effect of one explanatory variable on the response variable Y depends on the value of another explanatory variable . The purpose of using the moving […]

In a multistage decision problem, decisions and outcomes alternate. That is, a decision maker makes a decision, then some uncertainty is resolved, then the decision maker makes a second decision, then some further uncertainty is resolved, and so on. NARRBEGIN: […]

NARRBEGIN: SA_57_64 Amanda is a recent college graduate, and has just started her first job. She would like to know if she saves $5,000 per year out of her salary over the next 30 years what the distribution of the […]

Suppose a company sells two different products, x and y, for net profits of $5 per unit and $10 per unit, respectively. The slope of the line representing the objective function is: a. 0.5 b. -0.5 c. 2 d. -2 […]

Phone numbers, Social Security numbers, and zip codes are examples of numerical variables. The relative frequency of an event is the number of times the event occurs out of the total number of times the random experiment is run. Answer: […]

A car dealer in Big Rapids, Michigan is using Holt’s method to forecast weekly car sales. Currently the level is estimated to be 45 cars per week, and the trend is estimated to be 5 cars per week. During the […]

The effect of a logarithmic transformation on a variable that is skewed to the right by a few large values is to “squeeze” the values together and make the distribution more symmetric The coefficients for logarithmically transformed explanatory variables should […]

NARRBEGIN: SA_115_116 A used car salesman in a small town states that, on the average, it takes him 5 days to sell a car. Assume that the probability distribution of the length of time between sales is exponentially distributed. NARREND […]

A sample in which the sampling units are chosen from the population by means of a random mechanism is a a. probability sample b. judgmental sample c. stratified sample d. systematic sample Which of the following are true statements of […]

An interval estimate is an interval calculated from the population data, where we strongly believe the true value of the population parameter lies. We compute the five-period moving averages for all time periods except the first two. Answer: F The […]

NARRBEGIN: SA_79_90 The service manager for a new appliances store reviewed sales records of the past 20 sales of new microwaves to determine the number of warranty repairs he will be called on to perform in the next 90 days. […]

In order to construct a confidence interval estimate of the population mean , the value of must be given. In developing a confidence interval for the population standard deviation , we make use of the fact that the sampling distribution […]

If two random samples of sizes 30 and 35 are selected independently from two populations whose means are 85 and 90, then the mean of the sampling distribution of the sample mean difference, , equals 5. Based on the histogram […]

When the error variance is nonconstant, it is common to see the variation increases as the explanatory variable increases (you will see a “fan shape” in the scatterplot). There are two ways you can deal with this phenomenon. These are: […]

NARRBEGIN: SA_82_85 Below you will find summary measures on salaries for classroom teachers across the United States. You will also find a list of selected states and their average teacher salary. All values are in thousands of dollars. Salaries for […]

If a model contains uncertain outputs, it can be very misleading to build a deterministic model by using the means of the inputs to predict an output. This is called the: a. Law of Large Numbers. b. Flaw of Averages […]

The expected value of perfect information (EVPI) is the most the decision maker would be willing to pay for the sample information. In transportation problems, shipping costs are often nonlinear due to quantity discounts. Answer: T The F-test of the […]

In an ANOVA test, the alternative hypothesis is that at least one population mean is different from the others. If the sample is a good representation of the population, what percentage of the students in the population should we expect […]

Four different shapes of histograms are commonly observed: symmetric, positively skewed, negatively skewed, and bimodal. NARRBEGIN: SA_79_81 In an effort to provide more consistent customer service, the manager of a local fast-food restaurant would like to know the dispersion of […]

If Cov(X,Y) = – 16.0, variance of X = 25, variance of Y = 16 then the sample coefficient of correlation r is a. + 1.60 b. ” 1.60 c. ” 0.80 d. + 0.80 e. Cannot be determined from […]

In a simple regression with a single explanatory variable, the multiple R is the same as the standard correlation between the Y variable and the explanatory X variable. In conducting hypothesis testing for difference between two means when samples are […]

NARRBEGIN: SA_69_70 A sample of 40 country CD recordings of Willie Nelson has been examined. The average playing time of these recordings is 51.3 minutes, and the standard deviation is 5.8 minutes. NARREND (A) Construct a 95% confidence interval for […]

The certainty equivalent is the certain dollar amount a risk-averse decision maker would accept in order to avoid a gamble altogether. The adjusted R2 is used primarily to monitor whether extra explanatory variables really belong in a multiple regression model […]

A car dealer collected the following information about a sample of 448 Grand Rapids residents: Exact salaries of these Grand Rapids residents Education level (completed high school only or completed college) Income level (low or high) Car finance (whether or […]

NARRBEGIN: SA_83_86 A company produces two products. Each product can be produced on either of two machines. The time (in hours) required to produce each product on each machine is shown below: Each month, 600 hours of time are available […]

An estimator is said to be unbiased if the mean of its sampling distribution equals the value of the population parameter being estimated. NARRBEGIN: SA_121_124 A continuous random variable X has the probability density function: f(x) = 2 , 0 […]