Does my answer make sense/am I right?

Question:

1. Assess the hypothesis that the value of increasing tenure is more important in stores that start off with very low levels of tenure? In other words, is there any evidence of a non-linear effect of tenure on financial performance?

My Answer:

Yes, as a store with very low levels of tenure start to increase tenure, their financial performance also improves but eventually it plateaus. Once it reaches a high tenure, further increasing tenure has a negative effect on financial performance. This can be seen when running a regression on the stores with the highest profit since crew tenure has a negative coefficient versus in the regression for all 75 stores it was positive.

Regression for all 75 stores: