I have data on two events over a 25-year span of time. The data look like (example below):
Year Event_1 Event_2 1990 1000 800 1991 850 750 1992 1050 850 . . . . . .
And so on and forth. I'd like to see whether Event_1 and Event_2 are correlated. The figures in the example above are simply frequencies of occurrence of both events. I understand Pearson's product-moment correlation coefficient, but I'm not sure whether that's the best strategy for these data.
I've read about cross-correlation in this other post, but I've never done time-series analysis before. Regarding the data:
I'd like to see if Event_1 and Event_2 over time.
I suspect that Event_1 might cause Event_2, but it's just a guess (it could well be the opposite).
Any reference to the literature to get me started with this will be very appreciated.