statistics math 510

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Question 1

The frameworks discussed in Chapter 4 could be considered more specific examples of:

Answer

		The Statistical Thinking Strategy
		Statistical engineering
		The scientific method
		All of the above
		None of the above

4 points

Question 2

After running an ANOVA comparing the average years of experience between five different job classifications, we obtained a p value of .02. Which of the following would be a reasonable conclusion concerning the population in this case?

Answer

		We have strong evidence to state that the average years of experience between these job classifications is the same
		We have insufficient evidence to state that the average years of experience between these job classifications is the same
		We have strong evidence to state that each of the job classifications has a different average age
		We have strong evidence to state that at least two of the job classifications have different average ages
		None of the above

4 points

Question 3

We are testing the null hypothesis that the average monthly revenue between four insurance offices is the same. We obtained a p-value of .07. Which of the following would be an appropriate conclusion about the population?

Answer

		There is a difference between the average monthly revenues of at least two of the offices
		There is no difference between the average monthly revenues of the four offices
		All of the offices have different average monthly revenue
		There is a 93% chance that at least one of the average monthly revenues of one of the offices is different from the others
		None of the above

4 points

Question 4

For which of the following scenarios am I most likely to utilize a Chi-squared test?

Answer

		Comparing the proportion of employees who take 10 or more sick days a year between three manufacturing plants
		Comparing the amount of variation in age between employees at four call centers
		Determining if there is any evidence that an independent variable has a relationship with y in a multiple regression model
		Comparing the average retirement age between hourly workers and management
		None of the above

4 points

Question 5

What would happen (other things equal) to a confidence interval if you calculated a 99 percent confidence interval rather than a 95 percent confidence interval?

Answer

		It will be narrower
		It will not change
		The sample size will increase
		It will become wider
		None of the above

4 points

Question 6

We ran a taste-test to see which soft drink employees in our company prefer. We had 100 employees, selected as randomly as possible, taste test two brands and determine which they preferred. Which of the following would be a reasonable statistical analysis to determine if there is a clear preference among our employees?

Answer

		A two sample t-test
		A paired t test
		A confidence interval for a proportion
		A prediction interval for a proportion
		None of the above

4 points

Question 7

Results of regression analysis are often abused in the following ways:

Answer

		Using the model without understanding the context in which the model was developed and recommended for use
		Predicting outside the region of the data without noting the predictions are an extrapolation of the model
		Ignoring known scientific and economic theory regarding the model and its variables
		All of the above
		None of the above

4 points

Question 8

Models based on subject matter fundamentals (theory) are generally better than statistical models for:

Answer

		Deep understanding of the process being modeled
		Extrapolation - Predicting outside the region of the available data
		Quick development of models
		A and B
		All of the above
		None of the above

4 points

Question 9

If you had the following residual plots what would be your concerns regarding the adequacy of the model associated with these residuals?

Answer

		Model is adequate. There is nothing of concern in the residual plots
		No problem, the residuals are normally distributed
		Residuals plots exhibit curvature versus the fitted value, but that is not a big problem
		Residuals plots have non-random patterns suggesting that the model is not adequate.
		None of the above

4 points

Question 10

George Box tells us “all models are wrong but some are useful”. By this comment he means:

Answer

		Humans do not have the capability to develop good models
		Models approximate the underlying theory and can be useful in some situations
		We can never model the true state of nature
		B and C
		None of the above

4 points

Question 11

Tips for building useful models include:

Answer

		Reducing subjectivity by using computer algorithms to select model predictor variables
		Plotting the raw data and model residuals in a variety of ways
		Focus on keeping the models simple, not complex
		Validating the performance of the model
		A, B and C above
		B, C and D above
		None of the above

4 points

Question 12

What should one consider when analyzing the results of an experiment?

Answer

		Understanding of the science, technology and operation of the process being studied
		Creating graphical displays to aid in the analysis and interpretation of the results of the experiment
		Performing a statistical analysis to test the significance of the effects studied in the experiment
		All the above
		None of the above

4 points

Question 13

Identify the assumption that is NOT made when conducting an experiment:

Answer

		The measurement system is capable for all measured responses
		The factors being varied are those studied in the experiment. All other factors are being held constant.
		The process remains relatively stable during the duration of the testing
		The experimental variation is small
		None of the above

4 points

Question 14

A 32 experiment means that we are experimenting with:

Answer

		Two levels of three factors
		Two dependent variables and three independent variables
		Two go/no-go variables and three continuous variables
		Three levels of two factors
		None of the above

4 points

Question 15

Given the plot below, what might you suspect about factors A and B?

Answer

		The effect of A is not influenced by the level of B
		The effect of A depends on the level of B
		A has a larger effect on the response than B
		B has a larger effect on the response than A
		None of the above

4 points

Question 16

Which of the following purposes are served by replicating an experiment?

1.	Provide a means for estimating the experimental error
2.	Increase the number of treatment effects included in the experiment
3.	Improve the precision of estimates of treatments effects

Answer

		1 and 2 only
		1 and 3 only
		2 and 3 only
		All the above
		None of the above

4 points

Question 17

In evaluating data on our process outputs, four characteristics we might investigate are: central tendency, variation, shape of distribution, and stability. Which of the following tools would be most helpful to determine stability of the process?

Answer

		Scatter plot
		Histogram
		Pareto chart
		Run chart
		None of the above

4 points

Question 18

Answer

		Scatter plot
		Histogram
		Pareto chart
		Run chart
		None of the above

4 points

Question 19

Control limits were originally defined at the three-sigma level because:

Answer

		This level provides a good balance between the risks of having “false alarms” and missing special causes
		This level establishes tight limits for the process to minimize variation
		This level provides only 3 false alarms out of 1,000
		This level makes it difficult for special causes to occur
		None of the above

4 points

Question 20

What does it mean if capability index Cp is less than 1?

Answer

		Process spread is greater than the specification
		It is safe to assume the process will most likely meet or exceed the specification
		The process is unstable
		The process is off target
		None of the above

4 points

Question 21

A process is said to be capable if:

Answer

		The process consistently meets the customers needs
		The common cause variation is less than +/- 3σ
		The common cause variation fits within the specification limits
		The process is experiencing no special causes
		None of the above

4 points

Question 22

The Hidden Factory is:

Answer

		Where the real work is done; out of the view of the public
		A source of Increased costs and reduced process capacity
		Only present in manufacturing processes
		Created by the workforce to cover up mistakes and errors
		All of the above
		None of the above

4 points

Question 23

The primary goal of process mapping is to:

Answer

		Understand how the process as it is actually operated
		Create a context for problem solving
		Document the process steps including beginning and end
		All of the above
		None of the above

4 points

Question 24

Problem solving activities typically include:

Answer

		Reducing the number of persons employed by an organization
		Automating The process to remove the problem
		Find the person(s) who are causing the problems and take appropriate action
		All of the above
		None of the above

4 points

Question 25

Box, Hunter, and Hunter are quoted in this chapter as stating: “Data have no meaning in themselves; they are meaningful only in relation to a conceptual model of the phenomenon studied.” This critical point is related to which of the following principles of statistical thinking?

Answer

		An overall strategy is needed to guide data collection
		Statistical thinking applications typically start with subject matter theory, not data
		We typically need to collect data sequentially, at different points in time
		Data enables us to build statistical models that quantify variation in the process
		None of the above

4 points

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