@EthanR this means that you have more data points than the chart is intended to represent.
This issue has given me some heart burn for a while now as I believe that there is absolutely no value in displaying this message unless the person who is seeing it is the report designer.. There has got to be a way to disable it for the final visualizations.
The way to deal with it would be to either have smart grouping of data elements (for example on a map) or to lump all insignificant data points into an Other box or something (these are my wishes and not existing features of the product)
Every single time non technical users see these "warnings" they simple assume that something is wrong which is completely opposite of what the intention of the message is.
Everything was working fine before updating Dec 2017 Version but once i updated Dec Version it is showing error Showing Representative Samples, Please suggest how i fix this as i am showing points in Map