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

learn more… | top users | synonyms

2
votes
2answers
30 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
32 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
39 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
9 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 ...
1
vote
0answers
57 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
13 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
16 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
16 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
26 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
30 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
6 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
103 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
23 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
59 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
46 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
55 views

Random Forest OOB error rate in R

I am building my model in R and am using the randomForest package. ...
2
votes
0answers
37 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
25 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
12 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
4 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
18 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
703 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
41 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
168 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 ...
1
vote
0answers
31 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
151 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
46 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
37 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
117 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
127 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
28 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
46 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" ...
0
votes
1answer
41 views

When to exclude erroneous data point

Let's say that I have two data sets, A and B-- A records the number of oak trees across fifteen plots in one habitat, B records the number of oak trees across fifteen plots in a different habitat. ...
0
votes
0answers
15 views

Measuring dependence of variables with measurement errors and copulas

The weight of 100 subjects is measured twice resulting in the normally distributed $X_1\sim N(\mu_1,\sigma_1)$ and $X_2\sim N(\mu_2,\sigma_2) $. I am interested in the correlation between the ...
0
votes
0answers
37 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 ...
1
vote
0answers
25 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 ...
4
votes
1answer
92 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?
0
votes
0answers
25 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 ...
2
votes
0answers
27 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 ...
0
votes
0answers
16 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 ...
0
votes
1answer
44 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 ...
1
vote
1answer
35 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 ...
2
votes
0answers
29 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 ...
0
votes
0answers
51 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 ...
1
vote
0answers
92 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 ...
0
votes
0answers
8 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? ...
5
votes
2answers
90 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 ...
1
vote
0answers
32 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 ...
1
vote
1answer
1k 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 ...