All Questions
Tagged with uncertainty standard-deviation
24 questions
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When do I use standard deviation of a variable vs. error propagation of that variable when determining uncertainty?
Let's say I have 2 quantities to measure, $x$ and $y$. They do not have uncertainty but I can make repeated measurements to determine their uncertainty via standard deviation. Then say I want to find $...
Jonah George
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2
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148
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Relative vs. absolute error bars in log-scaled plots
There's conflicting info from seemingly knowledgeable sources about the correct way to show error bars on a log-scaled plot.
$log_{10}(x \pm \Delta x)$ shows the absolute error. On the one hand, it's ...
- 165
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Combining Variation and Uncertainty from Replicate measurements
I have 3 measurements from 3 independent experiments {m_1, m_2, m_3}.
I have another 3 measurements that are used to scale the m measurements {n_1, n_2, n_3} from the same experiment (different from m)...
- 11
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42
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Calculating the uncertainty of a very complicated variable
You have taken $N \gg 1$ measurements of a group of variables $V$. You want to estimate the value of a quantity $\mu$ that can be estimated from these variables. Fortunately you have a formula $\mu(V)$...
- 111
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132
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Calculate mean and standard deviation of the ratio of two dependent variables
I have an instrument of which I would like to understand the uncertainty on the measurements taken, so that every time that I perform a single measurement, I can apply the error obtained and therefore ...
- 111
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1
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475
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Neural network regression - predicting mean and standard deviation
I have a dataset where for the same input, you get slightly varying results. In the final dataset I am using there are 4 input/output pairs for every input where the input is exactly the same but the ...
- 45
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32
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How can you estimate uncertainty of a binary measurement?
I am working on an experiment which detects signals as a a function of time.
There can be a trigger, but no signal (0) or a trigger with a signal (1).
We are interested in how the ratio (likelihood of ...
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57
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Standard error, standard deviation and error propagation
I measured a quantity 100 times to get 100 measurements denoted as $x_1$, $x_2$, ..., $x_{100}$, with uncertainties as $e_1$, $e_2$, ..., $e_{100}$. Now if I want to report the average of these 100 ...
- 71
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28
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When to use standard deviation versus standard error in linear error propagation
I have a question about linear error propagation. Let's say that I want to use an equation to calculate n, where n = (PV)/(RT) (eq.1)
I only take one measurement of P, and one measurement of T, but I ...
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17
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Absence and presence of uncertainties in a data
In the photo attached, I am comparing the D, Ra, H, and AED values of Glutinous rice in Songkhla (see 4th to the last row) to the rest of the values. I understand why most of it has uncertainty ...
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Whats the best representation of variables with large uncertainty
When express results with uncertainty it's common that sometimes these uncertainty pass the limit allowed of the variable.
For example, training a classificator model with an expected accuracy we ...
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131
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Error propagation vs standard deviation (pure statistics question, no software involved)
First off, I'm new here, so I might have posted this question at the wrong place, but I don't really know where to post it and could really use some help here. Any insight would be appreciated.
My ...
- 43
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138
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Propagating uncertainties of constants in division
I have two constants, $A$ and $B$, with associated uncertainties $\sigma_A$ and $\sigma_B$, from observational errors, for example. I need to perform calculations with these constants, by for example ...
- 539
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39
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error propagation for derivatives
I have the following problem:
I have some data of a function f(x) with a set of 300 values of it associated to the same number of values of x including corresponding standard deviation σ(f) for each ...
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380
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Propagating error when taking the derivative
I have a function that corresponds to a set of $(X,Y)$ coordinates with a Gaussian uncertainty ($\sigma_Y$) for each point. What I want to do is now compute the gradient of this function and the ...
- 599
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22
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Expected value for max weight of two stones (given independent uncertainty in each) [duplicate]
If I have two stones A and B with estimated weights (and associated uncertainties) of
A=100 +/- 5kg
B=102 +/- 2kg
Is there any formula (or good approximation) to compute the expected value of ...
- 133
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95
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Uncertainty from equation involving fitted parameters [closed]
I want to estimate the uncertainty of a calculation which involves a quantity from a fitted mathematical model. More specifically, the end calculation would be something like:
P = x / A_tot
where I ...
- 11
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89
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How to quantify the uncertainty in a single value obtained from a large number of simulations
Im a physics student working on a project in which I have to simulate a machine that would order a bunch of molecules according to their mass. I want to get a quantitative measure of how well the ...
- 21
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30
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Quantifying the precision of estimates in repeated measurements
Suppose that I have three different time-series for per capita GDPs of countries. Let $X^j_{it}$ denote the GDP estimate of country $i$ in year $t$, made by organization $j \in {1,2,3}$ (so there are ...
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87
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Is standard deviation an accurate measure of uncertainty when the independent variable is unchanged?
I have collected data over time for the value of a dependent variable, which depends on a non-time variable. For each measurement (with a set value for the independent variable), would it be ...
- 125
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209
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Uncertainty on the standard deviation of data set, when the data points are uncertain
I have a set of four data points (x,y), and I would like to describe the spread of the data about the mean in both the x-direction and in the y-direction. Each individual data point has an uncertainty ...
- 31
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128
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How can we calculate the standard deviation of multiple values with different uncertainties each?
For example, if I have a set of readings, like:
13.4 +/- 0.5
14.5 +/- 0.7
12.8 +/- 0.6
13.9 +/- 0.4
14.8 +/- 0.5
How do I calculate the standard deviation of ...
1
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3
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207
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Learning measurement uncertainty; could not find any online resources
I'm currently writing a lab report on Atwood's machine, and the gist of it is that $a=a_{g}\tfrac{\left ( m_{2}-m_{1} \right )}{\left ( m_{2}+m_{1} \right )}$.
We're holding $\left (m_{2}+m_{1} \...
4
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2
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548
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How to approximate measurement uncertainty?
At the moment I use standard deviation of the mean to estimate uncertainty:
$$\sigma_\textrm{mean}=\frac{\sigma}{\sqrt{N}}$$
where $N$ is in hundreds and mean is a time series (monthly) mean. I
...
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