Determine the quadratic regression equation for the following data set.

\begin{tabular}{|c|c|c|c|c|c|c|c|c|c|c|}
\hline [tex]$x$[/tex] & 3 & 5 & 6 & 5 & 8 & 7 & 10 & 11 & 11 & 12 \\
\hline [tex]$y$[/tex] & -126 & -150 & -172 & -229 & -273 & -335 & -420 & -506 & -598 & -708 \\
\hline
\end{tabular}

A. [tex] y = -6.36897 x^2 + 41.3118 x - 200.937 [/tex]

B. [tex] y = -6.36897 x^2 + 41.3118 x - 188.429 [/tex]

C. [tex] y = -6.36897 x^2 + 37.3389 x - 200.937 [/tex]

D. [tex] y = -6.36897 x^2 + 37.3389 x - 188.429 [/tex]



Answer :

To determine the quadratic regression equation for the given data set, we follow these steps:

1. Define the form of the quadratic equation:
The general form of a quadratic equation is:
[tex]\[ y = ax^2 + bx + c \][/tex]

2. Fit the quadratic model to the data:
Using the given [tex]\( x \)[/tex] and [tex]\( y \)[/tex] values, we fit the quadratic model to determine the coefficients [tex]\( a \)[/tex], [tex]\( b \)[/tex], and [tex]\( c \)[/tex].

3. Determine the coefficients:
The quadratic model, after fitting it to the given data points, yields the following coefficients:
[tex]\[ a = -6.36897 \][/tex]
[tex]\[ b = 37.3389 \][/tex]
[tex]\[ c = -200.937 \][/tex]

4. Substitute the coefficients back into the quadratic equation:
Substituting [tex]\( a \)[/tex], [tex]\( b \)[/tex], and [tex]\( c \)[/tex] into the general form of the quadratic equation, we get:
[tex]\[ y = -6.36897x^2 + 37.3389x - 200.937 \][/tex]

Therefore, the correct quadratic regression equation for the given data set is:
[tex]\[ y = -6.36897x^2 + 37.3389x - 200.937 \][/tex]

So, the correct answer is:
[tex]\[ \boxed{y = -6.36897x^2 + 37.3389x - 200.937} \][/tex]