I have ran a simulation to get a set of data points represented in the image below:
The $x$ values range from 5 to 400 in units of 1 (discrete x axis).
It is clear from the grapical representation that dependent value decreases as $x$ increases. Can anyone suggest how can I test if the data converges to any number greater than 0? All I can be certain of is that at infinity it is greater or equal to 0 (from the nature of the experiment it can only get positive values) .