QMB 3200 – Exam 3 Questions and Correct Answers (Latest Update 2025–2026, Already Graded)

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QMB 3200 Exam 3 Questions and Correct Ans i i i i i i i



wers/ Latest Update / Already GradedQMB i i i i i



A3200
graph ofExam
i 3 Questions
the standardized iand
residuals plotted Correct
against values of the norma
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l scores that helps to determine whether the assumption that the error ter
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m has a normal probability distribution appears to be valid is called a:
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Ans: normal probability plot
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The tests of significance in regression analysis are based on assumptions
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about the error term ɛ . One such assumption is that the variance of ɛ, den
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oted by 𝝈2, is: i i i




Ans: the same for all values of x
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identify independent and dependent variables between advertising and
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sales

Ans: The independent variable is the advertising expenses, and th
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e dependent variable is sales.
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In regression analysis, the variable that is being predicted is the:
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Ans: dependent variable
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The tests of significance in regression analysis are based on assumption
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s about the error term ɛ. One such assumption is that the error term foll
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ows ɛ a(n)
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Ans: normal
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Influential observations always: i i




Ans: none of the above
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When studying the relationship between two quantitative variables, an in
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terval estimate of the mean value of y for a given value of x is called a(n):
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Ans: confidence interval
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When constructing a confidence or a prediction interval to quantify the rel
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ationship between two quantitative variables, the appropriate degrees of
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freedom are:
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Ans: n-2i




The value of the coefficient of correlation (r):
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Ans: can be equal to the value of the coeffi cient of determination (r
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2).


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An F test, based on the F probability distribution, can be used to test for:
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Ans: significance in regression
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The coefficient of determination:
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Ans: cannot be negative
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The mathematical equation relating the independent variable to the exp
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ected value of the dependent variable, , is known as the:
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Ans: regression equation
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Suppose a residual plot of x verses the residuals, y - ŷ, shows a non-
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constant variance. In particular, as the values of x increase, suppose th
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at the values of the residuals also increase. This means that:
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Ans: as the values of x get larger, the ability to predict y becomes le
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ss accurate.
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An observation that has a strong influence or effect on the regression resu
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lts is called a(n):
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Ans: influential observation
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