Sales (in 1,000 unit), prices (in dollar), and ad spending (in $1,000) of a new consumer goods product for 40 consecutive days within a selling cycle are given in the data excel file. Estimate the appropriate demand function for the product using regression analysis. Please note: since days are consecutive, they can be considered as continuous.

The model. This is something like Y = function(Xs), where Y is the dependent variable and function(Xs) is a linear function of the independent variable(s). Explain what the dependent variable and independent variable(s) are, respectively.