Random samplingLike countless data sets, I only have inadequate information on how the data was collected. Nonetheless,two potential issues are clear.Firstly, there are only 12 data points, which seems to be a very small data set to use to make any vitalinferences. Secondly, it seems like about over half of the stores have a square footage of over 50,000 sq.ft. This point suggest that I should be incredulous of my estimates.Variation in the independent variable(s)Because of the small sample size, there is considerable variation in square feet and variation in a store'srevenue. The concerning point is that there is not enough data between 4,000 to 50,000 of square feetfor stores.Zero mean of the error term conditional on the independent variable(s)The error term likely contains many factors that impact revenue but are not square footage. Forexample, the location of the store is likely to affect the revenue of a store but is excluded in the data