I am currently doing statistical software that supports POS software. They asked me to predict how this month's sale will be based on the same month but of previous years (5 years ago).
Example: Predict the sales trend for the month of March of this year. I currently have sales from March of the years 2013 to 2017, and based on that, I must predict how we should go in March of this year. The problem is that I do not know what to do, I have investigated linear regression, or trends but I still do not understand.
I think that I should predict day by day the sale of each of the days, each day would show as a scatter chart and from there I could extrapolate one more point to get the trend, but I have no idea either.
Any help will be welcome. Thanks.