How can I check how good a data is distributed.

Hi, I am doing some prediction and sometimes I have a good Y values well distributed along the prediction curve and sometimes I have only 2 extreme values or ever a lot of values in the beggining of the curve and a few in the end.

The plot below shows some Y values for the prediciton curve. In other words this shows the histogram of my data.

How can I check how good they are distributed. i.ie not having only 2 values values or few values in extreme postions.

Is there a mathematical function that checks how good your data is distributed? For me do not matter if it is normal skewed or uniform distributed. What matter is that I have a good dispersion of the values.

Thank you.

Kind regards

Rafael