the amount of change within a group.?

Question

i have 3 participants . measured at 4 different contexts.

 

i want to calculate which of the 3 participants showed the most variant results. meaning which of them exhibits the most change when measured in 4 different contexts.

 

so with the results i could say for example the second participant  is more consistent and showed no huge amount of change in different contexts.

while participant 1 showed very different results in the 4 contexts thus he\she is most influenced by contexts than the 2nd or 3rd participants.

 

----

 

im not sure if i should measure the mean then see the  standard deviation??

im doing this for data analysis and i have no idea how to calculate this!

 

thanks

 

Answer 1

It sounds like you want to determine the mean for each participant and then that participant's standard deviation.

 

The formula for the mean is 

_        ΣX_i

X  =  -----

          n

 

Where

 

_

X (X-bar) is the mean, ΣX_i is the sum of the 4 contexts for each participant and n is the number of contexts which is 4 in this case.

 

Then the variance is

         _

        Σ(X_i - X)²

σ² = -----------

             n

 

and the standard deviation is

σ = √σ², above.

 

Hope this helps.