The mean of the data is 15 all you gotta do is add all the number up and divide by the numbers added
I think the correct answer would be B. If the residuals for brand A form an increasing curve, and the residuals for brand B form a U-shaped pattern, then neither of the data is likely to be linear. In order to be linear, the residuals of both data set should be, more or less, linear or approaching linearity in nature. Therefore, the linear regression that was done would not give good results since it is only applicable to linear data sets. Also, you can say that the relation of the data sets of the products are not linear. It would be best to do a curve fitting for both sets by using different functions like parabolic functions.
It helps you narrow down to a smaller answer for example there is pi, (3.14159265359) and there is more and more to that number. It is now estimated to 3.14 because it would be almost impossible to work with pi if it wasn't estimated