Question 1206259
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Answer: {{{f(x) = -0.26x^2 + 22.59x + 23.03}}}


Explanation


I used GeoGebra to find the answer. I entered the data into the spreadsheet portion, then created a list of points based off it. Lastly I applied the <font color=red>fitPoly</font> function to that list to determine the regression model.
<a href="https://wiki.geogebra.org/en/FitPoly_Command">https://wiki.geogebra.org/en/FitPoly_Command</a>


It is possible to find the quadratic regression equation by hand, but it would be very tedious and take a while. It's recommended to use a specialized calculator instead.


Here is an article talking about it with the TI84 or similar style of calculators.
<a href="https://education.ti.com/en/customer-support/knowledge-base/ti-83-84-plus-family/product-usage/11931">https://education.ti.com/en/customer-support/knowledge-base/ti-83-84-plus-family/product-usage/11931</a>


Or here's an alternative calculator
<a href="https://www.statology.org/quadratic-regression-calculator/">https://www.statology.org/quadratic-regression-calculator/</a>

 
Another alternative (of many others) is to use a spreadsheet.
Feel free to explore your favorite calculator.
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