ok there was a question that my teacher told me i got wrong

the question asked me to compute the mean which I did...

then the question went on to tell me compute the mean with another observation equal to zero

then the part that he drew the line through was my response to this question

Write a sentence about the effect of the zero on Joey\'s quiz average that mentions this property...

my response

The property that this illustrate of the mean is the observations. Sense the number of observations increased but the sum of the observations stayed the same this brough down the mean by defintion...

ok he drew a line threw it and told me it was wrong so my question is how is this wrong?

What would a correct answer include?

Thanks for any Help!

It depends on what he taught in class, but I am guessing that what the problem was trying to illustrate is that arithmetic means are very sensitive to "wild" data, or erroneous data that are out of range. This is probably in preparation to the next topic, medians and mode.

What you have stated are mathematical facts and perhaps not considered as illuminating observations.

In your response, you mention the property of mean as the impact of increasing the number of observations while keeping their sum the same. However, this is not entirely accurate. When you add a new observation of zero to the set of numbers, the sum of the observations will increase by zero, which means it will remain unchanged. As a result, the effect on the mean will depend on the original set of numbers and their average.

To correctly answer the question about the effect of the zero on Joey's quiz average, you should consider the impact of this new observation in relation to the original set of numbers. Since zero is a value that lies below the average, adding it to the set will generally pull down the average. Therefore, a correct answer could be:

"The addition of zero to Joey's quiz average lowered the mean because zero is a value below the original average, causing a decrease in the overall average."