In analyzing the residuals to determine whether the simple regression analysis satisfies the regression assumptions, which of the following is true?
A) The histogram of the residuals should be approximately bell-shaped.
B) The scatter plot of the residuals against the dependent variable should illustrate that the variation in residuals is the same over all levels of .
C) Neither A nor B are true.
D) Both A and B are true.
Q. 2Assume that the year 2000 is used as the index base period and that sales were 12 million in the year 2000. If sales were 18 million in the year 2006, the simple index number for the year 2006 is:
A) 1.5
B) 6 million
C) 150
D) 0.666
Q. 3Which of the following is not considered to be a stepwise regression technique?
A) Forward selection regression
B) Optimal variable entry and removal regression
C) Backward elimination
D) Standard stepwise regression
Q. 4A p-chart is useful for:
A) analyzing whether a process for a measurable variable is in or out of control.
B) analyzing processes which yield attribute data.
C) determining what the most likely cause of defects is.
D) All of the above
Q. 5A study was recently performed by the Internal Revenue Service to determine how much tip income waiters and waitresses should make based on the size of the bill at each table. A random sample of bills and resulting tips were collected.
These data are shown as follows:
Total Bill Tip
126 19
58 11
86 20
20 3
59 14
120 30
14 2
17 4
26 2
74 16
Based upon these data, what is the approximate predicted value for tips if the total bill is 100?
A) 15.55
B) 20.61
C) 26.03
D) 12.88
Q. 6The following model:y = 0 + 1x1 + 2x2 + 3x1x2 +
A) is a linear model with interaction.
B) is a second order polynomial model.
C) is a composite model.
D) is a convex model.
Q. 7Which of the following statements is true?
A) The interval estimate for predicting a particular value of y given a specific x will be narrower than the interval estimate for the average value of y given a particular x.
B) The higher the r-square value, the wider will be the prediction interval based on a simple linear regression model.
C) The prediction interval generated from a simple linear regression model will be narrowest when the value of x used to generate the predicted y value is close to the mean value of x.
D) The prediction interval generated from a simple linear regression model will be widest when the value of x used to generate the predicted y value is close to the mean value of x.
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