# How do you use the prediction equation to predict the missing value?

## Being that the answers are in the back of my book, I don't seem to be getting the correct one. My prediction equation is correct: $y = 1.67 x - 3269.64$ Please help in explaining how the answer to the missing value is: about 87 million

Aug 10, 2016

Substitute the year ($2010$) for the missing data in place of $x$ in the predictor equation

#### Explanation:

Given
$\textcolor{w h i t e}{\text{XXX}} y = 1.67 x - 3269.64$
where
$\textcolor{w h i t e}{\text{XXX}} y$ is the number of households (in millions), and
$\textcolor{w h i t e}{\text{XXX}} x$ is the year

For the year $\textcolor{b l u e}{2010}$ this becomes
$\textcolor{w h i t e}{\text{XXX}} y = 1.67 \cdot \left(\textcolor{b l u e}{2010}\right) - 3269.64$

$\textcolor{w h i t e}{\text{XXXX}} = 3356.7 - 3269.64$

$\textcolor{w h i t e}{\text{XXXX}} = 87.06$

So $y$ (the number of households) is approximately $87$ million.