Looking for a formula to figure the impact on an average with additional inputs.

lets use individual input scores of 1 thru 5.
lets say that there  275 inputs are ready and the current average is 4.7

Is there a formula to easily calculate what impact an additional input of a value would have on the overall average?

Keeping in mind that each additional input value decreases the weighting of all current inputs.

additionally how can you determine the number of top score (5) inputs it would require to raise the overall average from the current 4.7 to 4.8 and to 4.9? Rounding is done at 2 decimal points.

thanks.

Amazing. Thank you.

if I may ask 1 question:

let say in the process of gathering the 135 additional 5 scores hoping to get to 4.8, a score of 1 was given. How far back would it alone set the process? How many more 5 score would it then take to recover from the low score and get to a 4.8 ?
to my unmathematical mind, because there is much more room between 4.7 and 1 than there is between 4.7 and 5, a low score would have a more significant impact on the average than a high score would. Is this a truth?

That's what I thought.

As the number of input values increases, the impact (good or bad) decreases, correct? If you had 550 input scores, double the original number,  to begin with would it then require double the amount of 5 scores to move up to 4.8 and 4.9? 270 and 1100 respectively? There comes a point where it almost impossible in a practical sense to increase the average but still exists a comparatively easy way for the average to drop.