Lets say there's 10 people, each give a rating out of 10 for the new batman movie.The average from the 10 ratings are (sum/10) = 8.7

now one of those 10 changes his rating to a 8, is there are way to calculate the new average without having to go through all the data again?

what about if one of the 10 deleted his vote? so you have 9 votes now and the old average of 8.7?

I assume there is no quick fix solution other than to simply re calculate everything... the problem is that theres 50,000+ votes

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