Tagged Questions

Measurement error is the difference between a measured value of a quantity and its true value.

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18 views

Distribution of average and median of a random variable [duplicate]

Suppose I have some random variable, which is defined by certain distribution (e.g. triangle or normal or some other). Suppose I do $N$ independent measurements on this random variable and then ...
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0answers
11 views

Measurement Error in Dynamic Linear Model

I have fitted a dlm model as follow: ...
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0answers
6 views

Tools for determining final error with mixture of correlated and independent sources of error

Preface: Not looking for an answer, but rather seeking an approach or set of approaches to deal with a complicated problem. Brief version: I have a single, analytical set of 3 equations with 8 ...
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1answer
11 views

error summary metric

I am working on trying to get a summary metric that summarizes the results of four models (M1:M5) and preferably ranges from zero to one, with one being the best model and zero being the worst model. ...
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0answers
81 views

Estimating the uncertainty of a bias and a scatter

I have one single set of observational data. Assuming I know the right answer for one property of this data set and then I use one tool to measure this quantity. To get an estimate of the amount of ...
6
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1answer
60 views

Selecting priors based on measurement error

How do you calculate the appropriate prior if you have the measurement error of an instrument? This paragraph is from Cressie's book "Statistics for Spatio-Temporal Data": It is often the case ...
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0answers
16 views

How do you scale percentage intervals based on absolute size?

If you were told the travel time from A to B is 5 minutes, you wouldn't mind if it took between 0 and 10 minutes. So happy within 100% of 5 minutes. If the trip took 5 hours (360min), you wouldn't ...
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0answers
12 views

logarithmic calibration and geometric mean - citation search

I have a logarithmic calibration line: MachineSignal = -3.21 log(concentration) + 21.9 It seems obvious to me, that if I have a triplicate measurement of concentrations (measured indirectly through ...
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0answers
17 views

Paired data with independent groups of treatment, how to plan and analyze?

I need your assistance, I am trying to design an experiment, and in order to do so I need to know how the data will be analyzed. The experiment in on rats. Each rat gets some treatment, and a measure ...
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1answer
51 views

Weighted principal components analysis

After some searching, I find very little on the incorporation of observation weights/measurement errors into principal components analysis. What I do find tends to rely on iterative approaches to ...
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0answers
32 views

Using least squares straight line fitting on experimental data with errors

I'm trying to fit a line into a graph with points that have errors both in the y and x directions. I found the following document on the subject: https://www.che.udel.edu/pdf/FittingData.pdf My ...
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0answers
12 views

measurement sampling error and heteroskedasticity

I was reading: A potential problem arises from the fact that the measurement (sampling) error associated with the regression beta may vary cross-sectionally. This may introduce heteroskedasticity ...
0
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0answers
33 views

What is task-loss function?

I looked into "Multi-Output Learning for Camera Relocalization" research and faced with the following part (2.2 The Direct Regression Approach): Given a set of RGB-D frames with known camera poses ...
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1answer
28 views

How I can measure an error in a bar plot?

This is my barplot. Model(red) is my estimated frequency at each X-axis vale (0-19) and actual is the frequency at each X-axis vale. How I can measure error of this estimating work in barplot? If I ...
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1answer
12 views

Is it possible to extrapolate experimental errors from a subsample of a population?

I'm working with a dataset consisting of degradation rates for proteins in an organism, a total of approx 3750 rates in total. Obtaining these rates is difficult, so the majority of rates are reported ...
2
votes
1answer
70 views

How to use factors (from CFA) as independent variable in Regression Analysis

I calculated 4 factors as latent constructs in a Confirmatory Factor Analysis (I use AMOS). Now I am wondering if it is possible to extract some kind of a factor score like I know it from Exploratory ...
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0answers
26 views

Evaluating mean-squared error

Hello I am running a Regression Tree experiment. I am new to Regression Trees, and I am using Mean Squared error to test my tree. I am confused because I am getting a large Mean Squared Error but I ...
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1answer
57 views

Implication of mutual information

EDIT For two signals or random variables to be independent, the mutual information (MI) must be zero. What does mutual information (MI) convey? What is the meaning of independence? Does it mean ...
3
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1answer
55 views

Are significance tests only about sampling error or other forms of variation also?

When we study differences between a treatment and control group in an experimental setting, we want to test whether those differences are big enough that we can conclude they are not simply due to ...
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1answer
135 views

Estimate average percentage error based on another gaussian measurement

I have a model where the error is proportional to the throughput. This is, the observations I got come from a measurement instrument that has some error and it measures material going through in ...
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0answers
344 views

using Root Mean Squared Error (RMSE) to compare models with different sample size

I'm using k-fold cross-validation to compare different models. I splitted my dataset in 6 chunks and used 4 random chunks as training set and the remaining 2 as a test set. Now I fitted n-different ...
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0answers
60 views

Performance of hierarchical clustering for binary data in R

I am trying to use Hierarchical clustering to see how well it performs in classifying a dataset which I previously know its true classification. I am new to clustering in general. I was able to draw ...
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0answers
31 views

What's the sample size required to confirm that two treatments are identical?

Goal: Determine if a machine is defective Say I am going to give the same treatment to a group of people. I have a machine that will randomly split them into $2$ groups before giving the same ...
4
votes
2answers
131 views

Standard deviation for a measurement that has two causes of uncertainty

I would like to know how to calculate the standard deviation for a measurement value $x$ when there are two separate sources of uncertainty, 1 and 2, each with known standard deviation, $\sigma_1$ and ...
2
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1answer
52 views

larger sample size or more accurate measurement?

This question is completely theoretical in the sense that I don't have any real data. Suppose I am designing a study, in which I will go measure N pairs of (X,Y), then the goal is to build a ...
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0answers
42 views

Significant digit 354 rule from Particle Data Group

The particle data group (PDG) has a particular rule to round the value of a measurement. You can find the complete description at this link (page 13). Summarizing: ... if the three highest order ...
8
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1answer
167 views

Linear regression model that best suit for data with errors

I'm looking for linear regression algorithm that is most suitable for a data whose independent variable (x) has a constant measurement error and the dependent variable (y) has signal dependent error. ...
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0answers
17 views

Parameter estimation of LMM with multiplicative measurement error in fixed co-variate - How?

I have a linear mixed model, with multiplicative measurement error on the fixed co-variate only (i.e. the random part is assumed to be measured without error). How could I best estimate the ...
0
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1answer
19 views

How to perform power analysis for repeated measures with observation error?

I am interested in producing two raster maps of the same areas but separated in time. I would like to take the average value of all pixels in each map and test if there is a difference in that mean ...
3
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0answers
40 views

Estimating the Marginal Effect of a Misclassified Binary Regressor Without Instruments

In ordinary least squares, we can use an errors-in-variables model when one or more of the regressors are measured with additive noise to ameliorate the effects of attenuation bias. We just need to ...
4
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1answer
43 views

Measurment error for two variables

I am interested in estimating the effect of security S on crime C in a given city over time (eight quarters) for twenty cities, so it's panel data. The problem is, instead of actual security spending ...
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0answers
51 views

Measure of accuracy or measure of agreement for continuous data with true values

I have two continuous variables. Variable $X$ represents the true values (basically it is atmospheric pressure measured via a barometer). Variable $Y$ represents a way to approximate the atmospheric ...
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0answers
31 views

Upper Bound of Measured Data

HW question I am having trouble on: My attempt at solving it: I thought part (a) was pretty straight forward until I worked it out and got the same value of K for K_upperbound which I assume is ...
1
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1answer
27 views

How to integrate observational errors in goodness of fit tests?

I have an astrophysical non-linear curve, specifically a power spectrum. I need to fit this curve with a model and obtain the goodness-of-fit (GOF). This gives me expected and observed values. The ...
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0answers
46 views

How to compare forecasting methods: based on ARIMA and curve fitting?

I'm making a project connected with identifying the dynamics of sales. My database concerns 26 weeks (so equally in 26 time-series observations) after launching the product. I want to make forecast ...
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0answers
22 views

Using aggregated data from a database with data from another

Let's say I have two databases, in the first (DB1) there is individual data on how much people trust in the government ($X_{j,r}$), and on the second (DB2) there is individual data on how much people ...
2
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3answers
158 views

Defining precision in a mechanical movement

I have a device which rotates on a stepper motor through a belt and pulley system. I would like to know both the positional accuracy and precision of this movement. It is of my opinion that this ...
0
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0answers
12 views

Weighted averages of a subset using fractions vs a frequency

So I have a bunch of scores 0-100 and a two sets of weights, the frequency which is the number of people in the sample with an average score among those people. Then I have another value that is the ...
0
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0answers
24 views

Logistic regression when a covariate is measured with known but heterogenous measurement error

Let $y$ be a binary variable and $x$ be a covariate measured with known heterogeneous measurement error: $x_{i}$ ~ $\operatorname{Normal}(x^{*}_{i},\sigma_{i}^{2})$. Now suppose the relationship ...
0
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0answers
78 views

Error in variables problem and maximum likelihood estimation in R

I am estimating cross-sectional regressions - fragment: lm(rate~liqamih.log+cap.log+F1+F2, data=x) of the R code listed below. F1 and F2 are the coefficients estimates of time series model. In ...
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2answers
377 views

How to compare measurements and uncertainties made with different measuring instruments?

I have two different measuring instruments, A and B, both measure the same physical property $x$ of an object but with different "quality": B gives measurements with a known uncertainty while I do not ...
5
votes
1answer
302 views

How to calculate relative error when the true value is zero?

How do I calculate relative error when the true value is zero? Say I have $x_{true} = 0$ and $x_{test}$. If I define relative error as: $\text{relative error} = \frac{x_{true}-x_{test}}{x_{true}}$ ...
3
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4answers
179 views

Can the use of dummy variables reduce measurement error?

If the continuous variables are measured with error, can the use of dummy variables mitigate the problem? For instance, IQ measures intelligence with error. So will using a dummy of high, medium, low ...
1
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0answers
32 views

Measurement error in nonlinear models, when can one ignore it? and what can one do about it?

Suppose you know there is measurement error in your system but you don't have any idea what the variance is. In my specific case I have a nonlinear model \begin{align} y_i&=\epsilon_i ...
1
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1answer
144 views

Weighted average of measurements with unequal errors

Suppose I have the numbers below. Consider them as results of some measurement. ...
2
votes
3answers
221 views

Importance of optimizing the correct loss function

I want to understand the importance of optimizing the correct loss function. Say that I am building a linear regression model $p$ for predicting some values $y_1,\ldots,y_n$. I choose to fit my ...
1
vote
2answers
93 views

Recovering true data from multiple noisy versions

I am trying to find if there is any way to get the true data from multiple noisy versions, but the true data has a peculiar property. Problem Statement Consider a matrix $F=[f_1, f_2, ... , f_n]$ ...
0
votes
1answer
64 views

Does measurement error include effects of moderator variables?

I am not very sure how to interpret measurement error correctly: as a constant, as a bias, or as a moderator factor? Is it presumed that measurement error includes moderator effects? Let it be in ...
0
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0answers
38 views

Is it always necessary to correct the sample correlations for a meta-analysis?

Some authors eg Hunter et al (1982) propose that we must correct sample correlations for the measurement error.It seems measurement error need not be corrected for when we take a recourse to the ...
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0answers
43 views

Regression with error in covariates

I am looking for some advice for a colleague who is dealing with regression models for which it is know, that the continuous covariate of interest $X_1$ was measured with error. More precisely, we ...