Question 1196550
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Given Data<table border = "1" cellpadding = "5"><tr><td>x</td><td>y</td></tr><tr><td>4</td><td>12</td></tr><tr><td>6</td><td>16</td></tr><tr><td>8</td><td>25</td></tr><tr><td>9</td><td>30</td></tr><tr><td>19</td><td>39</td></tr></table>
Use statistical software to compute the regression line equation. 
I used GeoGebra.
The regression line is approximately  y = 1.73x + 8.53 when rounding to two decimal places. This rules out choice D.


The equation y = 1.73x + 8.53 is in the form y = mx+b
m = 1.73 = slope
b = 8.53 = y intercept
These facts rule out choices A and B


Use software to compute the correlation coefficient r to get
r = 0.92488
which is approximate


Square that value to get
r = 0.92488
r^2 = (0.92488)^2
r^2 = 0.8554030144
r^2 = 0.8554
The coefficient of determination is approximately 0.8554
This rules out choice E.


So far we have eliminated: A, B, D and E


Let's plug in x = 10 into the regression equation
y = 1.73x + 8.53
y = 1.73*10 + 8.53
y = 25.83
This matches what choice C is showing. 


Answer: <font color=red>C) When X is 10, the estimated sales will be 25.83</font>
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