F(m) = 2.5 + 0.12m
if Natalie paid $6.82
6.82 = 2.5 + 0.12m
0.12m = 6.82 - 2.5
0.12m = 4.32
m = 4.32 ÷ 0.12
m = 36
The call was 36 minutes long.
The confidence interval is based on
mean square error. T<span>he </span>mean squared error<span> (</span>MSE<span>) </span><span>of an </span>estimator<span> measures the </span>average<span> of the squares of the </span>errors<span> or </span>deviations.<span> MSE is calculated by the formula attached in the picture, where Xbar is a vector of predictions, X is the vector of predicted values. </span>
<span>The expression of the square root of 19x must be simplified when x is equal to 28. This is because possible factors of 28 can be seen to be 4 and 7, and 4 is a perfect square. This means it can be pulled outside of the square root when evaluated. The other options include only prime factors that could not be pulled out. (3,5), (3,7), (1,41)
28 simplifies as such:
Sqrt(19*28) = Sqrt(19*4*7) = 2*Sqrt(19*7) = 2*Sqrt(133).</span>
A)

_________________________________
B)

Or

_________________________________
C)
