I have a dataset containing values representing monthly sales in hypothetical e-commerce website. First columns contains order of particular month (eplanatory variable) and the second column (dependent variable) is value of sales in this month.
month_order value
1 2591
2 2262
3 2531
4 2379
5 2106
6 2500
7 2345
8 2200
9 2385
10 2991
11 2219
12 2600
13 3000
Equation of linear regression for this data set is:
f(x) = 27,42x + 2278
Question: Because I would like to make a very simple prediction of sales value in next month and I have no another more suitable eplanatory variable, may I use month_order and predict linear trend? In my case it would be:
f(14) = 27,42 * 15 + 2278 = 2689
is this correct in a theory of a linear regression and can I count it in this way?