An Avid Football Fan Was in the Process of Examining $y = \beta _ { 0 } + \beta _ { 1 } x + \beta _ { 2 } x ^ { 2 } + \varepsilon$

question 17

Essay

An avid football fan was in the process of examining the factors that determine the success or failure of football teams. He noticed that teams with many rookies and teams with many veterans seem to do quite poorly. To further analyse his beliefs, he took a random sample of 20 teams and proposed a second-order model with one independent variable. The selected model is: $y = \beta _ { 0 } + \beta _ { 1 } x + \beta _ { 2 } x ^ { 2 } + \varepsilon$ .
where
y = winning team's percentage.
x = average years of professional experience.
The computer output is shown below:
THE REGRESSION EQUATION IS: $y =$ $32.6 + 5.96 x - 0.48 x ^ { 2 }$ $$\begin{array} { | c | r r r | } \hline \text { Predictor } & \text { Coef } & \text { SyDev } & \text { T } \\\hline \text { Constant } & 32.6 & 19.3 & 1.689 \\x & 5.96 & 2.41 & 2.473 \\x ^ { 2 } & - 0.48 & 0.22 & - 2.182 \\\hline\end{array}$$ S = 16.1 R-Sq = 43.9%.
ANALYSIS OF VARIANCE $$\begin{array} { | l | c c c c | } \hline \text { Source of Variation } & d f & \text { SS } & M S & F \\\hline \text { Regression } & 2 & 3452 & 1726 & 6.663 \\\text { Error } & 17 & 4404 & 259.059 & \\\hline \text { Total } & 19 & 7856 & & \\\hline\end{array}$$ Do these results allow us to conclude at the 5% significance level that the model is useful in predicting the team's winning percentage?

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Definitions:

Explanatory Variables

Variables in a statistical model that are used to explain variations in the dependent variable; also known as independent variables.

Qualitative Predictor Variables

Variables that categorize or describe data based on attributes or qualities, such as gender, color, or type, which do not have a numerical value.

Dummy Variables

Numerical variables used in regression analysis to represent subgroups of the sample in a study.

Regression Model

A statistical technique that models and approximates the relationship between a dependent variable and one or more independent variables.