try to explain this. anand/halle?
1. tells you that 4 smallest numbers in a set of 9 numbers have a mean of 150. that tells you nothing of number #5, which is the number you want to find to get to median.
2. same reasoning applies for this point
both points give you the following in simplified terms:
150, 150, 150, 150, x, 500, 500, 500, 500
x could be any number between 151 and 499, hence median is uknown.