# Homework Help: Error Analysis On Excel Questions

1. Jan 28, 2008

### BayernBlues

1. The problem statement, all variables and given/known data

The error part of my physics labs have been takin up a lot of time lately. Anyways, say I have 10 numbers for time measurements like 3.53 s, 5.32 s, 3.57 s, 4.89 s, 3.24 s, etc...
and my reaction time is say +/- 0.20 s. I want to average these 10 values out but I have to associate an error reading like with the final value so for example my final value would like like : avg time = 3.23 +/- 0.13 s.

How would I use Microsoft Excel to find that final error value? I know that I could find the standard deviation but that takes forever on paper, and what/how exactly would I propgate it with my reaction time?

2. Relevant equations

I think you'd have to use those statistics forumlas on Excel

2. Jan 28, 2008

### BayernBlues

ok to rephrase it, say I find my standard deviation to be 0.08947 using Excel. My reaction time is 0.20 s and my average value is 1.41 s. How would I incorporate/propogate the rxn time and stnd deviation to find the final +/- error value?

3. Jan 29, 2008

### andrevdh

The error in your avarage value is given by the standard deviation of the set of measurements divided by the square root of 10 - 1, thus divided by three. Your reaction time is incorporated automatically in the spread of the measurements.