Question 109026
The {{{MEAN}}} is the {{{arithmetic}}}{{{ average}}}, - just {{{add}}}{{{ up}}} the numbers and {{{divide}}} by how 
many there are:  
{{{((-10) + (-4) + 5 + 9 + 11 + 13) / 6 }}}
= {{{((-14) + 14 + 11 + 13) / 6 }}}
= {{{(11 + 13) / 6 }}}

= {{{24 / 6 }}}

= {{{4 }}}


The {{{MEDIAN}}} is {{{the- number- in –the- middle}}}. In order to find the median, you have to {{{put- the- values- in –order}}} from {{{lowest}}} to {{{highest}}}, then find the number that is exactly in the middle:
{{{-10}}}{{{ -4}}} {{{ 5}}}{{{  9}}}{{{ 11}}}{{{ 13}}}….your numbers are already in order from lowest to highest
 ...   {{{-10}}} {{{-4}}} {{{5}}}.....{{{  9 }}}{{{ 11 }}}{{{ 13}}}….
 ............................|............................
     since there is an even number of values, the {{{MEDIAN}}} is 
     between {{{5}}} and {{{9}}}, or it is {{{(5+9)/2=7}}}. 

The reason {{{7}}} is the median is because the median falls halfway between the numbers {{{5}}} and {{{9}}}.