Question

Can anyone help me with with these two math problems? They are the only ones I can’t figure out. What is the quadratic regression equation for the data set? 6/100, 3/110, 10/50, 3/90, 5/120, 15/30, and 9/70
A. Y = -0.175x^2 + 3.786x - 121.119

B. Y = -0.175x^2 - 3.786x - 121.119

C. Y = -0.175x^2 + 3.786x + 121.119

D. Y = -0.175x^2 - 3.786x + 121.119



what is the linear function equation that best fits the data set? (See Comments for graph)


A. Y= 2x-2

B. Y= 4x-11

C. Y= 4x-2

D. Y=x-2

Answer 1

Answer:

1. D. Y = -0.175x^2 - 3.786x + 121.119
2. A. Y= 2x-2

Step-by-step explanation:

1. The data generally goes down to the right, so the peak of the curve will be to the left of the y-axis. That means the x-coefficient will have the same sign as the x^2 coefficient (negative). The values near the y-axis are large positive values, so the y-intercept is positive. The equation with these characteristics is the last one:

... D. Y = -0.175x^2 - 3.786x + 121.119

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You can have your calculator or spreadsheet program write the regression equation for you. It will give you substantially the same result. (see the attachment)

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2. For estimating a regression line through data of this sort, it often works well to use the extreme data points: (1.5, 1) and (7.5, 13). If you draw a line through these points, you find that it passes through several other points on the graph, and it has a negative y-intercept. The slope of the line is ...

... (change in y)/(change in x) = (13 -1)/(7.5 -1.5) = 12/6 = 2

Only one of your answer choices has a slope of 2:

... A. Y = 2x-2