# Sound recorder uncertainity

1. Feb 12, 2009

### Davronbek

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

I have this lab report due to tomorrow, but I'm stuck in this problem. My teacher asked me to find the uncertainty for the values, max+min/2. But, i get a huge number, how can that be the uncertainty?

2. Relevant equations

1- 154g 110 115 120
2- 208g 116 117 117
3- 137g 107 108 107
4- 145g 119 119 118
5- 155g 118 117 117
6- 149g 115 115 115

Those are my results for my experiment. 1,2,3 etc represent the blocks, and the numbers are the recording in decibel (dbl) sound recorder.

3. The attempt at a solution

If I do it according to her. Max+min/2 i should get for nr1. 120+110/2=115 ? is that ±115? How can that be the uncertainty? I also attempted to do Max-min/2 for nr1= 120-110/2= 5 so is that ±5?

2. Feb 12, 2009

### Delphi51

should be (max - min)/2
This is a rough calculation of the spread in the data.
If you had more data, it would be worth doing the standard deviation, a more sophisticated measure of the spread in the data.

3. Feb 12, 2009

### Davronbek

So how do i present this uncertainty? +- (answer here) or?

4. Feb 12, 2009

### Delphi51

Yes, you would state the best value (the average) plus or minus the uncertainty.