how do you find the average

[redjay]

how do you find the average of a group of numbers?

[KebabMeister]

Sum of the numbers divided by the amount of numbers.

e.g. 10+5+15+12+14=56 divided by 5 (how many numbers there are) = 11.2

[*mystical*]

theres three ways isnt there?

mean mode and median

mean where you add all the numbers and devide it by how many numbers there are

mode is when you find the most common (a number out of the group of numbers that comes up the most)

median when you put all the numbers in ascending order and find the middle number, if there an even amout of numbers and the middle number is actually two numbers then you find the number half way in between them

[fo3nix]

mean: add up all numbers, divide by the total number of numbers.
example: 1,2,3,4,5. mean = (1+2+3+4+5)/5 = 3.

median: order the numbers from small to big, then select the middle one. if two numbers are in the middle, find the mean of those two numbers (see above).
example: 1,2,3,4,5. median = 3.

mode: most common number in a sequence.
example: 1,2,3,3,3,3,3,4,9,5,4. mode = 3.

range: largest number - smallest number.
example: 1,2,3,4,5. range = 5-1 = 4.


most common method is "mean".

[jake-the-peg]

Just because I can't resist confusing a perfectly simple question, there's also the geometric mean.

In this you mutiply the numbers together and take the

n th root of the product where there are n numbers

so the geometric mean of 1, 2 and 4 is the cube root of  (1 x 2 x 4)  or 2.

I'd never heard of the application of this but I hunted about and found this:

http://www.math.toronto.edu/mathnet/questionCorner/geomean.html

which made sense to me.

It's a sad day when you don't learn something new

[Octavius]

The question was about average, what are you lot rattling on about???

The average of 10, 20, 30 & 40 ( a group of 4 numbers) is:

15+25+35+45 = 120 divided by 4 = an average of 30

KebabMeister had it right, so what have you lot proved?  That you can't read a question?

[Octavius]

The question was about average, what are you lot rattling on about???

The average of 15, 25, 35 & 45 ( a group of 4 numbers) is:

15+25+35+45 = 120 divided by 4 = an average of 30

KebabMeister had it right, so what have you lot proved?  That you can't read a question?

[Octavius]

Well I learnt not to press submit too quickly!

[fo3nix]

Yes, also I believe that's exactly what *mystical* and I said...

[landie]

Add up all of the samples and divide by the number of samples.

[jake-the-peg]

Average is a number that typifies a set of numbers of which it is a function.

Adding up numbers and dividing by the number of items is one average - the mean. It is not always appropriate hence all the old jokes about families with 2.5 children - when did you last see half a child.

Hence there are other averages nicely summed up by mystical.

I know my example of the geometric mean was a bit fancy but I'm pretty sure mean, mode and median are GCSE syllabus.

[newtron]

Don't forget the harmonic mean which is the total number of values divided by the sum of the reciprocals of the values.  The arithmetic mean, geometric mean and harmonic mean are all used to estimate the average flow properties of complex hydrologic systems in groundwater hydrology.