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Fitting a straight line to a set of data yields the following prediction line. C

ID: 3250204 • Letter: F

Question

Fitting a straight line to a set of data yields the following prediction line. Complete (a) through (c) below.

Yi=120.9Xi

1. Interpret the meaning of the Y-intercept, b0. Choose the correct answer below.


A. The Y-intercept, b0=12, implies that for each increase of 1 unit in X, the value of Y is expected to increase by 12 units.

B. The Y-intercept, b0=12, implies that the average value of Y is 12.

C. The Y-intercept, b0=12, implies that when the value of X is 0, the mean value of Y is 12.

D. The Y-intercept, b0=0.9, implies that when the value of X is 0, the mean value of Y is negative 0.9.

2. Interpret the meaning of the slope, b1. Choose the correct answer below

A. The slope, B1=0.9, implies that for each increase of 1 unit in X, the value of Y is expected to increase by 0.9 units

B. The slope, b1=12, implies that for each increase of 1 unit in X, the value of Y is expected to increase by 12 units.

C. The slope, b1=0.9, implies that the average value of Y is minus0.9.

D. The slope, b1=0.9, implies that for each increase of 1 unit in X, the value of Y is estimated to decrease by 0.9 units.

3. Predict the mean value of Y for X=6.

Yi= ___?

Explanation / Answer

1)

The Y-intercept, b0=12, implies that when the value of X is 0, the mean value of Y is 12.

Answer is (c)

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2)

The slope, b1=0.9, implies that for each increase of 1 unit in X, the value of Y is estimated to decrease by 0.9 units.

Answer is (d)

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3)

For X = 6,

Y = 12 - 0.9*(6)

Y = 6.6