For example, take a look at these two graphs.

In the top graph it appears as though the five families make about the same annual income with the 3rd family making a little more money.

In the bottom graph it appears as though family 3 makes a much higher income.

Which graph is more representative of the data? 
The first graph!

When we look at the actual dollar amounts on the y-axis, we can see that the 3rd family's annual income does not differ greatly from the other 4.

Here is another scenario...

A production manager tells a potential buyer that his company is able to produce an average of 88,600 products per work week.

The buyer asks to look at the statistics for proof and this is what she found:

The production for one week were as follows:

• Monday - 50,000

• Tuesday - 224,000

• Wednesday - 62,000

• Thursday - 50,000

• Friday - 57,000

Was the average rate of production per week an accurate representation of the data?

No!!!  Tuesday's production was much higher than the other 4 days.

A more accurate average can be found by using the data from Monday, Wednesday, Thursday and Friday.  This would be 54,750.  This makes a lot more sense!!!