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

learn more… | top users | synonyms

0
votes
0answers
17 views

Clustering words by similarity and occurance

I have the following problem: I have a list of document terms and their frequency. These terms are not common English words. Numerous variants (i.e. spelling mistakes) relating to these terms are ...
0
votes
0answers
7 views

Distance error for object detection algorithm in point cloud

I have a point cloud that was produced with stereo camera. Because of stereo camera (central projection) the density of points drops with distance, so the point cloud has been "normalized" with a ...
1
vote
0answers
12 views

Computing bias due to measurement error:

I'm currently doing an exercise and faced with the following question: We have the true form: $y_i=\beta_0 +\beta_1 d_i +u_i $ Where $d_i$ is a dummy variable. We have measured $d_i$ with ...
0
votes
0answers
11 views

How can additional data with measurement error be used to improve the predicitve accuracy of a model on data without measurement error?

I have two data sets with 7 categorical variables. The first small dataset (100 samples) is the goldstandard and contains only values that are exactly like they are in the data. The second dataset ...
0
votes
0answers
9 views

Combined measurement uncertainty for mass computation

Problem I would like to determine the combined standard measurement uncertainty for a mean mass $\bar{m}$ computed from a mean volume $\bar{V}$ and a constant density $\rho$ with $\bar{m} = \bar{V} ...
1
vote
0answers
24 views

“cumulative” vs “additive”

I was reading a brief theory of measurement from ftp://ftp.sas.com/pub/neural/measurement.html when a passage got me stuck. It says that Consider a rat in a Skinner box who pushes a lever to get ...
0
votes
0answers
12 views

Error propagation: add errors in quadrature, or use a weighted standard deviation?

I have a measurement $x$ with a known uncertainty $\sigma_m$. I have a black box that can take an error-free measurement $x$ and produce a value $y$ with a known uncertainty $\sigma_{b}$ (which is ...
0
votes
1answer
13 views

Combining measurements with known uncertainties

I have $N$ rulers that each have a different but known level of accuracy, e.g. one's a meterstick, one's a yard stick, etc. I measure the length of my table using each ruler. How do I combine ...
2
votes
1answer
15 views

What method for forecasting error measuring in a poisson process?

There's so much different measures for the forecast error that I kind of lose the sight on which one to use. Out of the following: MAPE, ...
3
votes
2answers
127 views

Propagation of uncertainty through a linear system of equations, Ax=b, where A and b are correlated

I have a linear system of equations in the form Ax = b. The elements of A and b were experimentally determined and as such have some uncertainty. Within each row, A and b are correlated. Between rows, ...
1
vote
0answers
10 views

Propagation of errors including deviations

I have $n$ experiments, and for each experiment $i$ there were a variable number $m_i$ of measures $y_{ij}$ taken, which were combined resulting in a single measure $x_i = \frac{\sum_j y_{ij}}{m_i}$ ...
2
votes
0answers
25 views

The effect of Measurement error on a Beta Coefficient

I am trying to show the bias of the slope coefficient that occurs when there is measurement error in the regressor. $$ Y = a + B* x_{i} + e_{i} $$ To find the beta coefficient, we can use the ...
0
votes
0answers
21 views

How to calculate the per-pixel uncertainties of an image after convolving it with a 2D kernel?

I have one 2D image (let's call it "model image"), which is generated by evaluating a particular analytic model for each of its pixels. Since this is just a simple analytic model, there is no ...
0
votes
0answers
29 views

Chi square statistic when both model and data have errors

I have written a code which fits a model to some data. My model and data are two-dimensional images. To be more precise, I am fitting some kind of galaxy model to astronomical observations. The ...
1
vote
0answers
15 views

Error calculation from calibration data?

Suppose I have the following calibration data from a measuring instrument: ...
0
votes
0answers
39 views

Why is my R-squared so low when the relative absolute error is not that bad?

I feel this may be a slightly dumb question but I'm trying to predict the price of a good and I'm obtaining low r-square values (approx. 0.20) but, in my case, acceptable absolute relative error ...
0
votes
0answers
22 views

error measurement bias in dependent variable correlated with both the dependent and the independent variables

I have to estimate a model where because of a transformation of the dependent variable I now have a measurement error in the dependent variable that looks like Y^_i = Y_i (1+h_i). The reason why this ...
2
votes
2answers
40 views

Is CFA appropriate for test retest reliability?

I know CFA is often used when there is a latent variable that has measurement error that can attenuate correlations. However, does it make sense to make this same adjustment for measurement error when ...
2
votes
1answer
67 views

Converting between different accuracy/error metrics

I am trying to compare model accuracy between several different measurement metrics. For example, some citations use accuracy while other use error. That one is rather obvious, but there are lots of ...
4
votes
1answer
51 views

Measurement error in independent variable may not really matter?

In OLS, since measurement error in an independent variable biases its coefficient toward 0, if the coefficient ends up significant (with the expected sign), then is it true that the measurement error ...
1
vote
0answers
12 views

Precision of bone density measurement

I just did a precision study scanning 30 patients twice. The calculator presented the least significant change score, but how do I calculate my precision? For instance, the ISCD states that the ...
2
votes
0answers
91 views

Meta-analysis using experimental reliability data

I have a rather conceptual question. We measured experimentally the reliability of a certain readout. Now what I would like to do is to use this data to give a statement about the results of previous ...
1
vote
0answers
14 views

Detect grid in 2D plane

Given is a set of points (x,y) in a two dimensional Cartesian coordinate system. Many points are near the crossing points of an affine transformed grid. The points have been measured and may have: ...
0
votes
0answers
19 views

Calculating error in hourly/daily/annual duplicated observations

I'm hoping to determine the best way to describe and quantify measurement error in a salmon counting project I work on. Here's a description of the setup: Salmon passing upstream pass through a pair ...
1
vote
2answers
22 views

Adding Up Margins of Error

I'd like to add data from Census.gov, but I don't know how to add up the Margin of Error. Example, I have the estimate number of renters in Congressional District 1, (203,941 +/- 4,892) and the same ...
1
vote
0answers
30 views

Which statistical method should I use to compare test results of two groups with each other and with exact values?

I am currently working on an in-vitro medical device for an academy project with my teammates to see if our approach to a certain problem is working. We are hiring two groups of volunteers (15 people ...
0
votes
0answers
44 views

Bayesian Linear Regression for Noise-Free Data (using PyMC)

I was surprised to find out that fitting a straight line into "perfect", i.e. noise-free, data, results in rather large uncertainties for the estimated parameters. Example and Estimation Results ...
1
vote
0answers
8 views

Multiplicative Measurement Error in Response Variable

I understand that taking log of the multiplicative error model transforms it into the additive error model. Let $y'$ be the observed response variable, with $y$ being the true response variable and ...
2
votes
3answers
128 views

Relationship variance, accuracy, and precision?

I have built a measuring machine. It takes a photo of something and tells you how tall that thing is. I took three photos of the same object. On those three occasions, my machine said the object ...
1
vote
0answers
24 views

How should the error-term in reporting results be properly written to make sense?

I want to report results obtained from a number of measurements with the average value plus minus the standard deviation. During my studies I was always thaught to use only one signifying digit in the ...
0
votes
1answer
171 views

Testing significance of RMSE of models

I repeatedly trained two neural network models and calculated the RMSE for each run (split validation). Which statistical test is most useful in this case for testing if the difference of the models ...
1
vote
0answers
53 views

Shouldn't the root mean square error (RMSE) be called root mean square residual?

As far as I understand, estimating the error of a model, say an artificial neural network, requires to know the "true" model. Wikipedia says in its article "Errors and residuals": "The error (or ...
0
votes
0answers
107 views

Random Forest OOB error rate in R

I am building my model in R and am using the randomForest package. ...
2
votes
0answers
38 views

Measurement errors

Let $n$ points $(x_i, y_i)\in \mathbb R^2$ satisfy $$ ax_i + bx_iy_i + cy_i = 1,\, i=1,\ldots, n $$ Each point is observed with an error $\boldsymbol \varepsilon _i = (\varepsilon _i^x, \varepsilon ...
0
votes
0answers
30 views

Proper approach to Gamma-distributed data prediction with measurement errors in outliers

My task is to predict Gamma-distributed data with a large number of extreme-valued outliers caused by measurement error (i.e. the machine that records the values intermittently malfunctions). My ...
0
votes
0answers
15 views

measurement accuracy relation to sample size

I am measuring the volumes of a number, n, of physical objects with an accuracy of +/- 2%. I would like to estimate the total sum of the volume of all n objects. Each object is similar, but not ...
0
votes
0answers
5 views

Measuring / Characterizing error in ordered data

I have two sets of data points. The ground truth set and the measurement set. The magnitude measured is time, and it is important that each data point in the measurement preserves the order in the ...
0
votes
0answers
27 views

Measuring Prediction vs Actual Difference

To find error we usually measure our predicted y vs actual y. Are there any error terms that measure the error in y AND the error in x, given y? In the image below the line is doing a pretty good ...
9
votes
1answer
776 views

If “Standard error” and “Confidence intervals” measure precision of measurement, then what are the measurements of accuracy?

In book "Biostatistics for dummies" in page 40 I read: The standard error (abbreviated SE) is one way to indicate how precise your estimate or measurement of something is. and Confidence ...
0
votes
0answers
11 views

Is there any way, except calculating standard error and confidence intervals to indicate precision of the measurement?

In book "Biostatistics for dummies" in page 40 I read: The standard error (abbreviated SE) is one way to indicate how precise your estimate or measurement of something is. and Confidence ...
3
votes
1answer
52 views

Non-Significant difference between individual items, but significant difference between overall scores

Say that we have a scale measuring Healthiness of Diet, and want to see if two populations have different levels of Healthiness of Diet. If we find that the difference between the two samples at the ...
1
vote
1answer
190 views

correlation coefficient in linear regression

My interest is to develop a relation of the correlation coefficient when the data (both the dependent and independent variables) have measurement errors. Intro The measured values are related to the ...
2
votes
1answer
46 views

How to plot error ellipse knowing the VCV for xx,xy,xz,yy,yz,zz

I would love some guidance on if it is possible to plot error ellipses knowing what the title says and how to do it. The data has to do with GPS measurements and I need the error ellipses to find the ...
4
votes
1answer
199 views

Does linear regression assume uncertainty in the measurement of the variables?

Does linear regression assume uncertainty in the measurement of the independent variables (X), the dependent variable (y), or both?
1
vote
1answer
47 views

Measurement error should drives coef to zero

I have an output that puzzles me: I think the coef for sat in my eivreg should be lower than ...
0
votes
0answers
44 views

Regression measurement error - Classic Errors in Variables assumption - command in R

I need to handle measurement error in independent variables. I have the CEV case i.e. that $$CoV(x_1^*, e_1) = 0$$ where $x_1^* = ability$ (a persons innate ability) and $x_1 = sat$ (a test score). ...
0
votes
0answers
142 views

How to normalize root-mean-square-error for predicted values of multiple variables with different ranges

I am trying to compare different data mining algorithms (svm, linear regression etc) in their ability to predict a matrix where each column represents a different variable and has a different range. ...
0
votes
0answers
179 views

How to discuss RMSE, MAE, $R^2$ results. What values are good/bad?

I have regression results for a study where I'm trying to develop a predictive model to estimate the value of a continuous output value for a physical process. My database has around 400 records and ...
1
vote
0answers
32 views

Simple linear regression where the exact measurement error is known

I've been looking through a bunch of error-in-variables models, but I can't find one that matches what I'm looking for (if it exists). I am trying to do a simple (univariate) linear regression where ...
0
votes
2answers
47 views

What is the name of the 1/2 sum of square errors function?

What is the name of this function: $E = \frac{1}{2}\ \sum\limits_{n=1}^N \{ output_n - target_n\}^2$ Which is used in machine learning (e.g. error back prop). I have sometimes seen the name "MSE" ...