how to find assumed mean in statistics

"Count" the total number of xi (don't add it up and den divide) , suppose it's 8 den assumed mean would be 8/2 = 4 so the 4th xi will be the assumed mean but suppose the no is odd like 5 then A.M would be 5/2 = 2.5 i.e 3rd xi will be the assumed mean.

Hope its understandable!