You would need to give us the data set to answer this question. I'm assuming this is a stats question which means I'd need to see what set of data you are working with to determine if the mean or median is best to describe the center. The meadian is resistant to outlying values while the mean is not. Therefore the meadian is a better describer for skewed distributions. Whenever you have outliers the dataset is skewed. Take a look at the shape of the data. Does it look skewed? You can make a simple graph with the data points to determine if there are outliars if you aren't able to tell just from looking at the data. (Again I don't know what data you are working with, but I hope this helped)
