posted by Wanda .
why is the population shape a concern when estimating a mean
What is your School Subject?
If the shape of the population distribution follows the Normal curve, the mean coincides with the mode and median, and hence it's is meaningful as an indicator.
On the other hand, if it is skewed, i.e. does not follow the normal curve, other indicators may be more meaningful, depending on the "shape" of the distribution curve.