Hello,
First you have order all the number least to the greater. That gives 30, 75, 80, 85, 85, 95, 95, 100, 100, 110.
Afterwards you have to find the median. Why ?
I will explain you. It's because the median is robust. In fact, it can't be influenced by extreme values (example : 110) but the mean yes. So the mean won't be accurate.
"Then why don't you choose the mode ? " you will ask me. That's because the mode takes the number which appears most often in a set of numbers. It couldn't be accurate at all. It will be useless for this set of numbers.
Furthermore, here there are 3 numbers which appears the most ( 2 times for each) : $85, $95 and $100. Which one will you take ?
Therefore the median is the most suitable and the most accurate to know the center because it is robust.
Now, let's find the median :
There are 10 values, so the median will be the average of the 5th and 6th values.
5th value = 85
6th value = 95
Therefore the median is 90.
Hope this helps !
Photon
