All Questions
Tagged with measurementsdata-analysis
42 questions
4votes
2answers
1kviews
Error analysis via two different methods
We have a quantity $a$ expressed in terms of two quantities $b $ and $c$ as $a = b/c$. It seems to me that there are two ways of estimating the error on $a$, the "physics" ...
21votes
7answers
2kviews
Line of Best Fit with or Without Constant Term
Some other physics teachers and I were discussing an AP problem about a potential experiment for measuring $g$ and disagreed on the best way to use a line of best fit to analyze the data. The ...
- 7,369
1vote
1answer
155views
Uncertainty measurements done with multiple devices
so I need to calculate the volume of a cylinder. I have measured both the radius and the height with three different devices (ruler, calipers, micrometer), each of them 10 times (total 90 measurements)...
- 11
2votes
0answers
40views
Finding the uncertainty of a value after taking the average [duplicate]
Recently I did a measurement experiment where I measured the diameter of a piece of wire using a micrometer. I tested it 4 times. I got 0.87, 0.89, 0.90,0.90 respectively. The units being millimeter. ...
2votes
1answer
53views
Degree of accuracy to express $T$?
I conducted a pendulum experiment and here are my results: 10T / s: ( The time taken for 10 oscillations measured on a stopwatch that only shows the time to 2 decimal places. Measured in seconds ) For ...
-1votes
2answers
172views
Is there a fundamental limit to the precision of calculations?
For daily applications, it is accepted that there are limitations to the precision of our calculations when we want to compute quantities that are rational multiples of irrational numbers. Then ...
2votes
4answers
787views
Uncertainty formula for division
$$(A \pm a) \times (B \pm b)=AB\left(1 \pm \frac aA \pm \frac bB\right)$$ Here is the formula im struggling with, I'm just trying to apply this formula for division (i.e for speed, $\frac dt$, instead ...
- 157
4votes
2answers
1kviews
Rules of significant figures, precision, and uncertainty
In the physical sciences (which are physics, chemistry, astronomy, materials science, etc.), we learned that the uncertainty is +/- the smallest unit (which is 1) of the last significant figure if the ...
3votes
2answers
292views
Error calculation for a relative difference with only one standard deviation (STD)
I have a quantity that is calculated with two measurements, but I only have a tabulated standard deviation for one of the measurements. How would I calculate the error on the calculated quantity? The ...
1vote
2answers
78views
Different fitmodels for different intervals
A number of points were measured and plotted on an XY graph. I want to have the best fit line for this graph. The best fit model for the first part of the graph is described by some function $f_{1}\...
- 257
1vote
2answers
560views
How to quantify the uncertainty of the time series average?
Usually, we measure a fixed physical quantity, then we simply average MEAN on the measurement results and calculate the standard deviation STD, then the measurement result can be written as MEAN±STD. ...
- 11
0votes
4answers
420views
In a least squares fit, is the resulting error in the fit parameters considered statistical/random error or systematic error?
In a least squares fit, if there is no error estimate on the input data points, is the resulting error in the fit parameters $\sigma_y$ (which is calculated from residuals) considered statistical/...
3votes
2answers
777views
Determining the appropriate number of significant figures to report in least squares analyses
I'm tasked with fitting a set of data to a line using Excel's $\text{LINEST}$ least-squares fitting routine. The data are $l$ and $m$ values, assumed to follow the relationship: $$l = l_0 + {g\over k}...
- 829
1vote
3answers
359views
Validity of power law fit (and analytical fit choice)
Context I am carrying out molecular dynamics simulations of trapped ions in a radio-frequency field of amplitude $U_{RF}$ + DC (see details https://arxiv.org/abs/2102.04098). I am studying radio-...
- 41
0votes
1answer
175views
Uncertainty propagation time difference
So for an experiment we gathered time data. It a rolling object, where t2 and t1 are measurements of one whole roll of circumference. We estimated time uncertainty at 5 ms. So then estimation of ...
- 2,237
