A Study Examined the Number of Trees in a Variety

Essay

A study examined the number of trees in a variety of orange groves and the corresponding number of oranges that each
grove produces in a given harvest year. Linear regression was calculated and the results are below.
linear regression results:
Dependent Variable: oranges
Independent Variable: trees
Sample size: 9
R-sq = 0.886
s = 31394.7
- $\begin{array}{|l|r|r|}\hline \text { Parameter} & \text { Estimate }& \text { Std. Err. } \\\hline \text { Constant }& 390.59 & 16328.8 \\\hline \text { Trees }& 525.84 & 71.22 \\\hline\end{array}$

Since $r^{2}$ is not 100%, there must be other factors in influencing the number of oranges harvested. What percentage is that and what is another factor you think might be involved?