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

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17 views

Why do the residual sum of squares and the mean absolute percentage error conflict with each other?

I carried out regression with 7th degree and 8th degree polynomials. As expected, the residual sum of squares for 8th degree polynomial regression is less than that of 7th degree polynomial ...
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20 views

Hypothesis Testing with limited resolution

Assume two univariate, normal distributions e.g. A~N(x,0,1) and B~N(x,1,1). Assume that we receive a value e.g. t=0.2 (e.g. via measurements) We want to perform hypothesis testing and decide if t ...
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1answer
45 views

What is Cronbach's Alpha intuitively?

I'm trying to understand Cronbach's Alpha intuitively. What is the general idea behind this construct? What properties were they trying to ensure that it had?
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22 views

How do I calculate needed sample size

I am measuring visitors to a website in an A/B test (i.e. showing two different versions randomly to visitors and comparing what % converts). I am trying to calculate an estimate for what sample size ...
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12 views

Systematic/measurement error on a linear regression

Suppose I have a set of data ${(x_i,y_i)}$ in which the uncertainty in the measurements ${(\Delta x_i,\Delta y_i)}$ (which come from the propagation of systematic errors from the measurement ...
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9 views

Cox model with known measurement error

I am trying to perform a univariate Cox PH survival analysis in R. My covariate was generated from another analysis, meaning that I have a 95% CI range (between 0 and 1) for the values. Right now, I ...
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1answer
24 views

Error propagation and relative error

Say I have measured the value A = 50 +- 2 and from this I am calculating the value: B(A) = A^2 From what I understand I calculate the new error using error propagation to be delta_B ...
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1answer
32 views

What is the standard way to distinguish the errors associated with sampling and measurement in statistics?

This is probably a very basic, yet not easy, question in applied science. I was just wondering, what are usually the standard ways to deal with it? Any pointers to further references are greatly ...
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16 views

How to consider propagated measurement errors and “statistical errors”

I come from an Engineering background, and I am familiar with some basics of error treatment. However, discussing with a friend over some data he had to analyze, we couldn't quite figure out what to ...
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27 views

To work out 7 point Likert scale sample size, can I increase the MoE to 7%?

I have a survey that consists of 7 point Likert scale data. Each sample is quite expensive to collect, so I'm trying to keep the sample size as small as possible without compromising the results. My ...
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23 views

What is the correct way to interpolate error?

If I have a 2-D data, say $y = f(x)$, with error in the dependent variable, $\delta y$ in this case, and I want to interpolate this data set to a coarser independent variable grid, $x$, what is the ...
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4 views

Similarity measurement akin to SMAPE

I have two questions: A) Is there an official name for average of the smaller number over the larger number? B) Why have SMAPE range from 0 to 2? Isn't a range from 0 to 1 superior for understanding? ...
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2answers
59 views

How do I include measurement errors in a Bernoulli experiment?

I would like to understand how to combine a known measurement error in a Bernoulli experiment with the confidence interval in order to calculate error bars. I am performing an experiment that has two ...
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18 views

Calculating MASE Scores for Individual Participants

I have run a controlled experiment in which 30 participants made one step ahead forecasts under two separate conditions. I want to know if there is a difference in error scores between the two ...
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1answer
225 views

ImageNet: what is top-1 and top-5 error rate?

In ImageNet classification papers top-1 and top-5 error rates are important units for measuring the success of some solutions, but what are those error rates? In ImageNet Classification with Deep ...
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31 views

Computing Test Statistics when Measurements have Error

Edited to better represent sources of measurement error I have 2 groups of subjects(say male and female centipedes) that I made measurements on(Average length of the subject's leg). The measurements ...
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1answer
23 views

Determine RMSE for tracing an object on a touchscreen

I have a study in which participants have to trace two computer generated objects (a circle and a square) shown on a touchscreen. I need to calculate how accurately they are able to trace these ...
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24 views

Error on histogram computed on autocorrelated time series

I am struggling to find an answer to this quite basic question. When computing a histogram on a time series which has some correlations (i.e. measurements are not independant), how to estimate the ...
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1answer
29 views

Standard Error for Weighted Values

I want to calculate the standard error for an experimental measurement. The data is stored as a 2D image which is circularly symmetric about a center point. To reduce the data we radially integrate ...
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181 views

Bayesian modelling, measurement error & carrying-over posterior distributions

I have a (fairly convoluted, but well-inentioned) model in my head, and am trying to figure out if it's possible to code (I am currently getting to grips with R2WinBUGS). The final model is basically ...
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37 views

What determines the precision of uncertainties?

What limits the precision with which you can describe the uncertainty of a measurement? I will describe two examples that feel qualitatively different, but I am not sure if they are quantitatively ...
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0answers
60 views

How to measure error in linear regression?

Suppose I have $X, Y =$ {$(x^{(1)}, y^{(1)}); (x^{(2)}, y^{(2)}); ...; (x^{(m)}, y^{(m)})$} examples with: $x^{(i)} \in \Re^n$: for $i$ $\in$ [1;m], $x^{(i)}$ = {$x_1^{(i)}, x_2^{(i)}, ..., ...
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2answers
135 views

Is it true that $E[Y|W]=E[Y|E(X|W)]$, given that $W$ is $X$ measured with error

In Carroll's 2006 book "Measurement Error in Nonlinear Models", and on p38 it is stated without proof that: [One can] estimate the regression of $Y$ on $(Z, X)$ and then to substitute into this ...
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4answers
69 views

Poor sample measurement and the Central Limit Theorem

I have a fairly basic question about the Central Limit Theorem. I understand it in principle, but I like to know specifically what happens when there is poor measurement on the samples. Say for ...
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33 views

Testing interactions with non-normal ordinal data

I am testing a hypothesis in which my scale DV (PSS) is predicted by an interaction between an Ordinal DV and a scale IV. The ordinal IV is TF (Total Freq) The scale IV is and PQM (Practice ...
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1answer
11 views

Measuring dispersion of data points

I have a number of data points (which can be small) with measurement error bars. I assume the intrinsic values are drawn from some sort of normal distribution. What is the most robust method for ...
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18 views

Error propagation and Standard Deviation

I never quite got the hang of this during my entry stat course and it has been bugging me for a long time now. Lets assume I'm trying to find the focal length of a concave lens. Using a mockup ...
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51 views

Making Predictions in an Error in Variables Model

Say I have estimated some parameters $\hat{\beta}$ between input $x$ and output $y$, according to a generalised linear model $y=x^T \beta$, by using the Least Squares method. I can then easily make ...
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1answer
46 views

Question on error minimization, bias and variance

I have been using Matlab to approximate a density function using histograms with a fixed number of bins. The histogram is on the interval $[-10,10]$ with a bin size of $0.05$. This makes 400 bins. ...
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46 views

Calculate the Hamming Distance between the two same datasets

How to Calculate the Hamming Distance between two datasets of same points?Both the data sets look exactly the same. http://postimg.org/image/u11qnsolh/ There are two datasets of same number of ...
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1answer
120 views

The effect of covariate measurement error on coefficients in regression with dummy variables

I am trying to understand if I should be more concerned with covariate measurement error in linear models including dummy variables, than with all continuous predictors. Say I have a simple linear ...
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1answer
72 views

Errors vs measurement errors

I'm reading about how to fit a straight line with measurement errors in both coordinates ($x$ and $y$). Let the true unobserved variables be $x_{t,i}$ and $y_{t,i}$ and the observed variables be ...
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30 views

MSE of training set and validation set for linear regression

The wikipedia article on cross validation http://en.wikipedia.org/wiki/Cross-validation_(statistics) makes the claim that "under mild assumptions that the expected value of the MSE for the training ...
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34 views

How to fit quantized data

I have some measurements which were quantized during measuring. Now I want to get the overall change during a period of time, e.g. 15 minutes. Because of quantization however, the same value is ...
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1answer
85 views

Is it necessary to correct the d-statistic for measurement error while doing a meta-analysis? [closed]

Hunter, Schmift snd jackson advocate its correction for measurement error. Is it always necessary? can we do it without correcting such effect sizes?
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32 views

Is it okay to use relative error on a set of measurements rather than an absolute error?

As far as I've learned, if you have a set of measurements and the differences between the average of those measurements and the individual measurements aren't always smaller than the absolute error of ...
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19 views

Interaction model with measurement error without replicate measurements

I am currently working on a simple OLS model with two independent variables and one dependent variable: \begin{equation} \ Y_i = \beta_0 + \beta_1 X_i + \beta_2 S_i + \beta_3 X_iZ_i \end{equation} ...
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46 views

Propogation of error in a matrix inversion

I'm trying to find the deterministic error bounds for some parameters calculated through distance geometry. The equation can be simplified to the following form: $ \left[\begin{matrix} x_1 \\ x_2 \\ ...
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21 views

How do you report percent error with limited precision?

Let's say you have an experimental data point with limited precision, such as 0.67 ± 0.1, and a known actual value such as 0.72. What is the standard way to report the percent error in this case, ...
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19 views

How should I handle measurement error in logistic/probit regression and what are its effects?

I am concerned with the problem where dependent discrete variable $R$ is to be modelled by continuous predictor $X^*$, which is subject to measurement error $u$ of the form $$X^*=X+u$$ ($X$ being the ...
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52 views

Accounting for measurement bias using a histogram or violin plot and numerical data in R

The Problem I have a gardener whose job it is to measure trees in meters using a measuring stick. She measures the heights of 1,000 trees. I plot these measurements on a violin plot in R. I am ...
3
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1answer
72 views

non-classical measurement error in a binary outcome model

I have a binary outcome model that I am estimating with a probit, so $$\Pr(Y=1\vert x,z)=\Phi(\alpha +\beta\cdot x^* + z'\gamma)$$ I am interested in the marginal effect of $x^*$ on $\Pr(Y=1\vert ...
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1answer
590 views

Additive Error or Multiplicative Error?

I'm relatively new to statistics and would appreciate help understanding this better. In my field there is a commonly used model of the form: $$P_t = P_o(V_t)^\alpha$$ When people fit the model to ...
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1answer
21 views

IV or latent factor to process multiple measures?

I have several measures on different memory tests. I consider these measures may actually measure different aspects of memory functioning and every measure contains a measurement error. I am thinking ...
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51 views

Robust Measures for Forecast Accuracy

I am doing a forecast using robust exponential smoothing methods and to determine / measure the forecast accuracy I want to use robust measurements as well. As I am not really familiar with robust ...
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91 views

Machine learning/random forests with noisy response data

Machine learning techniques like random forests seem to assume that the responses in the training set are known perfectly. Specifically for regression applications, it seems one needs to account for ...
2
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1answer
83 views

Accounting for unknown error in multiple regression?

I have a very naive question about multiple regression and errors...one that isn't addressed here already (Choosing a robust estimator to account for measurement error in dependent variable) I would ...
2
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0answers
29 views

does the area under the curve (AUC) has some interpretation? [duplicate]

I know that the ROC curve plots true positives vs false positives, but does it have any other interpretation, or is it just an arbitrary performance measure? Also, in the case of very unbalanced ...
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22 views

Need to determine stability of a measure over subsets

I have a measure that takes a set of data and spits out a value. I want to determine the stability of this measure in terms of the size of the dataset. I.e, I want to understand how the returns (for ...
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41 views

Measurament error from semivariogram

I am looking at a model to determine the measurement error for a set of measurements of a spatially correlated phenomenon (sea surface temperature measurements) using a semivariogram technique. For ...