# Predicting the EPC increase based on last 4 months and previous year

I have the following information: EPC (earnings per click) for the previous 12 months across an entire portfolio of websites are:

$$\begin{pmatrix} Jun 18 & 0.11 \\ Jul 18 & 0.12 \\ Aug 18 & 0.15 \\ Sep 18 & 0.16 \\ Oct 18 & 0.15 \\ Nov 18 & 0.19 \\ Dec 18 & 0.24 \\ Jan 19 & 0.15 \\ Feb 19 & 0.17 \\ Mar 19 & 0.15 \\ Apr 18 & 0.14 \\ May 19 & 0.17 \end{pmatrix}$$

For one specific website in that portfolio, the EPC over the past 4 months are

$$\begin{pmatrix} Feb 19 & 0.89 \\ Mar 19 & 0.97 \\ Apr 18 & 0.93 \\ May 19 & 1.14 \end{pmatrix}$$

Making assumptions that no other external factors can affect EPC and that the industry is cyclic (i.e the increase in December will happen again), how do I go about predicting the EPC for November/December this year?

I initially calculated Z scores for the yearly EPC and was going to use this to calculate the probability that the EPC will increase at the same rate, however I don't think that is possible here.

I am effectively trying to do a simple linear regression model but with my dependent variable being my independent variable?

How could I go about trying to figure out a rough EPC prediction based on this?

The reason I don't want to open the regression model to what it should be (i.e multi variable regression model with clicks and earnings) is because a) I am making this in Excel so I'm not sure how to write it up and b) because I have to present it tomorrow and I'm not sure if I will be confident in it in time.

Edit: I changed my tactic slightly. What I did was calculate the average EPC across the entire year. I then worked out how much of an increase the EPC in November and December had, against the average yearly EPC.

From this, I can see that there is an increase in EPC around 16& in November and 34% in December.

The average EPC for the listed website has been around 1.012.

So assuming this is line with the yearly average, I can predict that this EPC will increase by 16% in November and 34% in December. Can this work? I hate using average's so much, but is there another way?

I know, 100%, that this is a really bad model to predict EPC on. But like I mentioned, with the time I have I'm not able to do it using the multi linear regression model and so need a patch up job.