Tagged Questions
0
votes
1answer
98 views
Is it possible to measure the true distance between two objects? [closed]
Could we measure an accurate distance between two objects or do we get a number with an infinite amount of decimals? A number with an infinite number of decimals are an infinite amount of data, so I ...
-3
votes
1answer
39 views
How many measurements should be done? [closed]
I am measuring time of a computer operation. The operation should run roughly same time each time I measure it. How many times should I measure it to get good average and standard deviation?
1
vote
1answer
38 views
Measurement uncertainty of the quantity, that is function of two others quantities
I'm trying to compute uncertainty for the density of the ball.
I measured its radius 6 times, so I was able to compute the stastistical uncertainty (we call it uncertainty type A, I don't know, if ...
2
votes
2answers
48 views
Asymmetric uncertainties
Inspired by these two question on tex.SX
Asymmetrical tolerancing
Asymmetric uncertainties with siunitx package
I'd like to ask for a nice explanation for these kind of uncertainties, like ...
0
votes
0answers
44 views
About the resolution/$\sqrt{12}$ uncertainty
Suppose you want to measure a (real-valued) quantity with an apparatus which will return as a result of the measurement the closest integer to the true value of the quantity.
Then, a common use is to ...
2
votes
1answer
55 views
Is this the correct way to I combine multiple interdependant pressure readings?
I want to measure the density in different layers of a suspension. To do this I want to place pressure sensors at different heights. Let's assume that the sensors are not by orders of magnitude more ...
2
votes
1answer
52 views
Multimeter has a resistance
If a multimeter has a resistance (1M ohm, say) when measuring voltages how do I take that into account in my error?
2
votes
0answers
350 views
How to calculate uncertainties of a natural exponential function?
(I apologize if this should be posted in mathematics, however I chose to post it here as it's technically about physics)
I conducted an experiment in which position of items were shifted on an ...
2
votes
0answers
138 views
How do I do error calculus right using gnuplot as an example?
Given is a set of measurements with their respective errors for example an energy spectrum. In gnuplot one is to fit a function $ f(x;\{p_i\})$ depending on a variable $x$ and on fit parameters $p_i$. ...
0
votes
3answers
218 views
Significant Figures
Subtract 0.2 J from 7.26 J. Express your answer to the correct number of significant figures for the given data.
I think its 7, but the answer is 7.1. HOW?
1
vote
1answer
494 views
Calculating the Uncertainty for an Average Value [closed]
How would I calculate the uncertainty for the average of this set?
$32.5 \pm 0.1$
$32.0 \pm 0.1$
$32.3 \pm 0.1$
3
votes
1answer
988 views
How to combine the error of two independent measurements of the same quantity?
I have measured $k_1$ and $k_2$ in two measurements and then I calculated $\Delta k_1$ and $\Delta k_2$. Now I want to calculate $k$ and $\Delta k$.
$k$ is just the mean of $k_1$ and $k_2$. I thought ...
2
votes
1answer
238 views
Is $\sigma$ or $\sigma / \sqrt{N}$ is error of a measurement?
I wonder whether $\sigma$ or $\sigma / \sqrt{N}$ is error of a measurement. When I measure, say $0, 1, -1, 1, -1$, I have a $\sigma = 1$. I just measure $0, 1, -1$, I also have $\sigma = 1$.
But in ...
5
votes
3answers
912 views
How to combine measurement error with statistic error
We have to measure a period of an oscillation. We are to take the time it takes for 50 oscillations multiple times.
I know that I will have a $\Delta t = 0.1 \, \mathrm s$ because of my reaction ...
3
votes
2answers
122 views
Question about uncertainty
Are $3.43\pm 0.04$ $\frac{\mathrm{m}}{\mathrm{s}}$ and $3.48$ $\frac{\mathrm{m}}{\mathrm{s}}$ within expected range of values?
The answer is yes, but I do not clearly see why this is so. I appreciate ...
3
votes
3answers
354 views
Calculating uncertainties for a final result
Say you are dividing 2 times with uncertainties:
$$\frac{t_1}{t_2} ~=~ \frac{0.551s \pm 0.002s}{ 0.712s \pm 0.002s}.$$
After doing the calculations you get:
$$\frac{t_1}{t_2} ~=~ 0.774 \pm ...
0
votes
1answer
96 views
How can constants… change?
I recently noticed that the value of Planck's constant has changed on Wikipedia. The value that I had in mind (from Google), $6.626068\cdot{}10^{-34}\text{J.s}$, has changed to ...
