statistics
posted by statistics .
basically i'm at the begining of the text book doing summer work
it's talking about mean and stuff
asked to find the mean of a set of data and given 14 different numbers
the question then goes on and tells me
a fifteenth number is added to the set of data with the value of zero find the new mean which i did
it asks
what property of the mean does this sitation illustrate?
I do not know what exactly it's asking me here it obviouly made the mean go down but what does it mean by property of the mean??
i do not know how to answer this question

One of the properties of the mean is that all numbers of the data set contribute equally (have equal weight) to calculate the mean. Therefore it can be distorted or affected by extreme values, or noise, or errors.
I suppose that the last value you added was way off the other values.