Im not a statistitian, although I have some reasonable education in mathematics.

This isn't a homework question (I'm 37 lol), its just something I have been working on as a personal project lately.

The following graph represents the % payout of an online video slot game. I have collected data points comprising of 25 spins on this slot, recording the return to player (RTP) of each group of spins. This has then been charted, grouping into 10% bands using a pivottable. There are 150 data points forming this data set.

As you can see, it has begun to resemble some kind of probability distribution. I was thinking initially a Poisson distribution. However, my attempts to map a true Poisson curve to this data have failed.

So I would like to request some help to:

a) find out which type of probability distribution this resembles; and

b) help me estimate the parameters that will enable me to plot the theoretical probability curve onto this experimental data set.

To my mind, the curve I need will not be symmetrical. As you can see from the chart, there is a significant one sided tail to the distribution. There is no tail on the left hand side because obviously there is a hard threshold at zero RTP.

Any help appreciated.

Thanks

Dan