Mean can mean you are being rude or in math terms it is adding a set of numbers then dividing by the total amount. ex. If your numbers are 1,2,and 3 add them to get 6 and divide by 3. You get 2.
The mean distance is the same as the mean of a set of numbers,but this time, instead of them just being numbers, they're lengths. You just simply add up all the numbers and divide the total length,...
It is the planar elongation eithr internal or extending to the surface of an end or edge due to gas voids, ingot shrinkage cavities etc.It can be tested from the method of Ultrasonic Testing.