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] & 0 & 2 & 3 & 3 & 5 & 6 & 6 & 9 & 9 & 9 \\
\hline [tex]$y$[/tex] & 493 & 500 & 487 & 477 & 452 & 429 & 383 & 324 & 260 & 180 \\
\hline
\end{tabular}

A. [tex]$y=-5.26917 x^2+10.5458 x+378.87$[/tex]

B. [tex]$y=-5.26917 x^2+10.5458 x+492.13$[/tex]

C. [tex]$y=-4.10134 x^2+10.5458 x+378.87$[/tex]

D. [tex]$y=-4.10134 x^2+10.5458 x+492.13$[/tex]



Answer :

To determine the quadratic regression equation for the given data set, we proceed as follows:

1. Data Points:
[tex]\[ \begin{array}{|c|c|c|c|c|c|c|c|c|c|c|} \hline x & 0 & 2 & 3 & 3 & 5 & 6 & 6 & 9 & 9 & 9 \\ \hline y & 493 & 500 & 487 & 477 & 452 & 429 & 383 & 324 & 260 & 180 \\ \hline \end{array} \][/tex]

2. Quadratic Regression Form:
The general form of a quadratic equation is:
[tex]\[ y = ax^2 + bx + c \][/tex]
We aim to find the coefficients [tex]\(a\)[/tex], [tex]\(b\)[/tex], and [tex]\(c\)[/tex].

3. Calculation of Coefficients:
After performing the necessary calculations (i.e., fitting a quadratic curve to the data points), we determine the coefficients as follows:
[tex]\[ a = -4.10134, \quad b = 10.54582, \quad c = 492.13 \][/tex]

4. Forming the Quadratic Equation:
Using the calculated coefficients, we can now form the quadratic regression equation:
[tex]\[ y = -4.10134x^2 + 10.54582x + 492.13 \][/tex]

Thus, the quadratic regression equation for the given data set is:
[tex]\[ \boxed{y = -4.10134x^2 + 10.54582x + 492.13} \][/tex]

From the given options, the equation that matches is:
[tex]\[ \boxed{y=-4.10134x^2+10.5458x+492.13} \][/tex]