find the mean and the median
-7,-1,3,9,10,16


Rule for finding the mean, which is the same as the 
old-fashioned average, which you learned how to find 
back in in the fifth or sixth grade.    

Count the numbers and add the numbers. It doesn't matter
whether you count them first or add them first.  But when
you have done both, you divide what you got when you added
them by what you got when you counted them.  Then what you 
get is the mean.

I will count them first. -7,-1,3,9,10,16
I see six numbers there.
Now I will add them:

I'll start with 
-7

then I'll add -1 to -7, getting -8,
then I'll add 3 to -8, get -5,
then I'll add 9 to -5, get 4,
then I'll add 10 to 4, get 14
then I'll add 16 to 14, get 30.

Now I'll divide 30 by 6, because there 
are six numbers in the list,  So I divide
that and get 5.

Rule for finding the median.

1.  List the numbers in order either from smallest to largest
    or from largest to smallest. It doesn't matter which.
2.  Count the numbers.  
    A. If the number of numbers is odd, pick out the number 
    located in the very middle of the list.  That number is the
    median.
    B. If the number of numbers is even, pick out the pair of 
    numbers which are located in the very middle of the
    list, then find their mean, or old-fashioned average.
  
-7,-1,3,9,10,16  

They are already arranged smallest to largest.

There are 6 of them. That's an even number so I pick out 
    the pair of numbers which are located in the very 
    middle of the list, they are 3 and 9. Now find
    their mean, or old-fashioned average, by adding them,
    getting 12. Then counting them, getting 2, then 
    dividing 12 by 2 and getting 6.
    So the median is 6.  

Edwin