Could it be that the image statistics plugin is not working anymore? In version 2.1.2 it did not work, I upgraded to 2.1.7 and it also does not work. In older versions it created a bar which showed the progress, for example. Thanks!
You probably have a frame range with a single frame in input. Go to the "Info" tab of the settings panel, press refresh and check that.
I only read a single video and apply Image Statistics.FrameRange in the Settings/Info tab isOk.I tested it in two different computers.
I also got no output on image statistics.
In Natron 2.2.3 ImageStatistics seems to work fine with the Analyze Sequence option.