Answer:
1. The question that asks about the relationship between two events can be "Did advertising affect the sales of a TV or not?"
2. The Scatter plot along with the Regression line is shown below.
3. This Residual plot indicates a linear relationship because it is a straight line (If we have a curve, not a straight line then it will be a non-linear relationship between sales and advertisement. As the advertisement for TV is increased it increases the sales of TV.