As Part of a Study at a Large University, Data $x _ { 1 } =$

question 65

Multiple Choice

As part of a study at a large university, data were collected on n = 224 freshmen computer science (CS) majors in a particular year. The researchers were interested in modeling y, a studentʹs grade
Point average (GPA) after three semesters, as a function of the following independent variables
(recorded at the time the students enrolled in the university) : $x _ { 1 } =$ average high school grade in mathematics (HSM)
$x _ { 2 } =$ average high school grade in science (HSS)
$x _ { 3 } =$ average high school grade in English (HSE)
$x _ { 4 } =$ SAT mathematics score (SATM)
$x _ { 5 } =$ SAT verbal score (SATV)
A first-order model was fit to data.
A $95 \%$ confidence interval for $\beta 1$ is $( .06 , .22 )$ . Interpret this result.

• A) We are \(95 \%\) confident that the mean GPA of all CS freshmen after three semesters falls between .06 and .22.
• B) \(95 \%\) of the GPAs fall within .06 to \(.22\) of their true values.
• C) We are \(95 \%\) confident that a CS freshman's HS math grade increases by an amount between \(.06\) and \(.22\) for every 1 -point increase in GPA, holding \(x _ { 2 } - x _ { 5 }\) constant.
• D) We are \(95 \%\) confident that a CS freshman's GPA increases by an amount between .06 and .22 for every 1 -point increase in average HS math grade, holding \(x _ { 2 } - x _ { 5 }\) constant.

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