1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Formulating a mean formula

  1. Nov 28, 2016 #1
    1. The problem statement, all variables and given/known data

    I'm trying to formulate a formula based on an experiment I did.

    2. Relevant equations

    3. The attempt at a solution



    x_1 = mean (one of 5 mean values)
    x_i = value of variables (there are 4 of them added together)
    n = number of variables

    My problem is, for the left hand side of the formula, I want to show that there are 5 means, so x_1 to x_5 = the right hand side as shown

    I'm not sure how to show this mathematically.

    Wonder if anyone might be able to help.

    Last edited by a moderator: Nov 28, 2016
  2. jcsd
  3. Nov 28, 2016 #2


    Staff: Mentor

    I don't understand what you're doing.
    ##x_1## is one of the four values in your summation. ##\bar{x_1}## is the mean of the four values. Since your summation runs from 1 to 4, I assume you mean for n to be 4, not 5 as you seem to indicate.
    With n = 4, we have ##\bar{x_1} = (1/4)(x_1 + x_2 + x_3 + x_4)##
    For the four numbers you're adding, there is only one mean.
  4. Nov 28, 2016 #3
    Thanks for reply.

    I'm just trying to let the person who reads the formula know that I have used this formula to calculate 5 mean values x_1, x_2, x_3, x_4 and x_5.


    result number one x_1 of 5 results x_5











    The data above is one of 5 sets of data for which I have to calculate the mean.

    For this data, I calculated the mean using my formula x_1= 1/4 (Sum of Yellow, Orange, Purple, Black) = 367.5

    I did this 4 more times with 4 other data sets just like this one.

    Does this make sense what I'm trying to do?
  5. Nov 28, 2016 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You need something like:
    ##\bar{x}_i = \frac14 \sum_{j=1}^{4}x_{ij}##

    Where ##\bar{x}_i## is the average of the ##i##th set of data ##x_{i1} \dots x_{i4}##
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted