The data below are the number of absences and the final grades of 9 randomly selected students from a literature class. Find the equation of the regression line for the given data.What would be the predicted final grade if a student was absent 14 times? Round the regression line values to the nearest hundredth. Round the predicted grade to the nearest whole number Number of absences X 0,3,6, 4,9,2, 15,8,5 Final grade Y 98,86, 80,82, 71,92, 55,76,82

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Answer:

The regression equation is:

Final Grade = 96.14 - 2.76 Number of absence

A student who was absent for 14 days received a final grade of 58.

Step-by-step explanation:

The general form a regression equation is:

[tex]y=\alpha +\beta x[/tex]

Here,

y = dependent variable = Final grade

x = independent variable = Number of absence

α = intercept

β = slope

The formula to compute the intercept and slope are:

[tex]\alpha =\frac{\sum Y. \sum X^{2}-\sum X.\sum XY}{n.\sum X^{2}-(\sum X)^{2}}[/tex]

[tex]\beta =\frac{n.\sum XY-\sum X.\sum Y}{n.\sum X^{2}-(\sum X)^{2}}[/tex]

The value of α and β are computed as follows:

[tex]\alpha =\frac{\sum Y. \sum X^{2}-\sum X.\sum XY}{n.\sum X^{2}-(\sum X)^{2}}=\frac{(722\times460-(52\times3732)}{(9\times460)-(52)^{2}} =96.139\approx96.14[/tex]

[tex]\beta =\frac{n.\sum XY-\sum X.\sum Y}{n.\sum X^{2}-(\sum X)^{2}}=\frac{(9\times3732-(52\times722)}{(9\times460)-(52)^{2}} =-2.755\approx-2.76[/tex]

The regression equation is:

Final Grade = 96.14 - 2.76 Number of absence

For the value of Number of absence = 14 compute the value of Final grade as follows:

[tex]Final\ Grade = 96.14 - 2.76\ Number\ of\ absence\\=96.14-(2.76\times14)\\=57.5\\\approx58[/tex]

Thus, a student who was absent for 14 days received a final grade of 58.