Say I am running a store and I have the daily customer count for the last 5 years.
1) I note that the average customer count is three times higher than the average for the rest of the year. 2) I build a table with two columns:
IsDayBlackFriday (0 or 1), Customer count (integer)
and run linear regression where the independent variable is customer count and the independent variable is whether it is a Black Friday or not. As expected, the p-value for both the model and black friday is extremely low, but the R-squared is also quite low. I reason that I am not bothered by it since I am aware that there are many other factors that determine the demand, and I am really looking for some statistical validation of the correlation between the two, and not trying to build a predictive model for customer count.
My questions are:
a) Can I conclude that on Black Fridays, I should hire 3 times more people as compared to the rest of the year to cover the demand, assuming the staffing requirement increases linearly with the customer count? For example, if on normal days, I have a staff count of 5, will hiring 15 people be a "statistically informed" decision?
b) If not, what can I really infer from the facts given above that I can translate to an informed decision? Should the staffing question be approached differently?