Percentage of starch	Hardness
2	4.3	4	4.8	4.6	5.1
5	6.5	7.3	7	6.4	6.8
10	9	7.9	8.5	8.3	8.9

A pharmaceutical company wishes to evaluate the effect of the amount of starch on the hardness of the tablets it produces. It was decided to produce samples of tablets with a certain minimum amount of starch, 2%, 5% and 10%. The data obtained by replicating the experiment five times are shown in the following table.

Construct a simple linear regression model for the response variable of the experiment.