Questions tagged [measurement]

Measurement is the assignment of a value (numeric or otherwise) to an observation.

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What scale of measurement is percentage?

Is the percentage of marks scored by someone or something like the population growth ratio scale of interval? Like both have an absolute zero so it makes sense for them to be ratio and not interval?
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What is a "method factor" in confirmatory factor analysis and structural equation modeling?

Researchers employing structural equation models and confirmatory factor analyses often choose to include a "method factor" in their models. My understanding is that this is intended to ...
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What are the pre-requisite of a dataset's measurement type before Principal Component Analysis can be used? [duplicate]

Must all the measured data be discrete, continuous, nominal or ordinal? What are some of the transformation techniques that can be used?
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Prior selection in Gaussian - an application to height measurement

Say I have just purchased ACME's Tree Height Measuring Device (THMD). ACME states that the error $\epsilon$ in tree height measurement from this device can be modelled as a normal distribution with ...
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How to express the agreement between experiment and theoretical observation?

Let us suppose I have a value measured from experiment and given by $$V_{\text{exp}} \pm \sigma_{V_{\text{exp}}}$$ and a theoretical value given as $$V_{\text{the}} \pm \sigma_{V_{\text{the}}}$$ Is ...
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Understanding Scales of Measurement

Looking through the various Stack Exchange groups, I think this may be the appropriate group. Apologies if I should have posted this elsewhere. I have been reading about Scales of Measurement (Nominal,...
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Accounting for sampling effort of independent variables in a regression analysis

I would like the test whether the frequency of a cellular structure on a histology section is associated with (binary) patient outcomes. This would be a simple logistic regression of i.e. ...
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How to summarise mixed binary and left-censored (limit of detection) continuous 'indicator' variables to give read out on continuous latent variable?

I have 4 measures {y1, y2, y3, y4} from n=350 patients, each uses a different method to detect or quantify the presence of the same biomarker, X. I want to estimate the "true" value of the ...
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When do we REALLY need to distinguish interval from ratio measurement levels?

This question is specifically aimed toward the practice of statistics and data science and toward statistics educators (particularly introductory level statistics). In brief, ¿when do we really need ...
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Welch-Satterthwaite equation for effective degrees of freedom

Using Welch-Satterthwaite equation to calculate the effective degrees of freedom i got 0.29, is that possible? What is the meaning of that equation and how can i know if I messed up somewhere?
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Measurement error and type I. and type II. error

Is there a relationship between measurement error (1.) both systematic and random, (2.) systematic only and (3.) random only in terms of tendency of results of statistical tests to be biased towards ...
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Term for how well a measure correlates with measures of related but different constructs

Is there a term that refers to how well a measure correlates with measures of related but different constructs? I suspect that there should be some such term, probably including the word "...
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Build an index to determine a ranking [duplicate]

Suppose we have a dataframe similar to the following (I have more than 3 columns and all values ​​in the dataframe are in %): ...
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Estimate uncertainty of window average

I have some random process $y(t)$ that represent an unknown signal combined with some random high frequency positive feedback noise, that is noise amplitude grows with the value of the signal. I think ...
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Metrics to compare diversity of groups on multiple characteristics

When I search for 'diversity metrics' it seems like most work has focused on ecological diversity, and I most frequently see the Simpson diversity index. This is equivalent to the economics metric, ...
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measurement invariance in experience sampling research [repeated measurement within individuals]

Experience sampling involves repeatedly sampling individuals with the same questionnaire multiple times a day for numerous days. I have two groups of people and I want to check for measurement ...
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What is the best way to handle longitudinal data where the follow-up question for the same outcome/construct has changed

I'm doing secondary analysis on a large longitudinal dataset (didn't collect myself) and have a series of questions related to movement/time-use behaviours (sleep, physical activity, sedentary ...
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Is body temperature interval or ratio scale?

I understand that temperature is interval scale because it holds no true zero and can represent values below zero. But in case of body temperature it cannot go below a certain point and definitely not ...
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How to express uncertainty on a measurement with bounded range of values, like humidity, or level in a tank

Could someone provide some hints on how to express the uncertainty on a measured quantity like humidity, or level of a liquid in a tank? Assuming the instruments provide a more or less constant ...
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Example of a measurement variable that can be multiplied but not added

In Stevens' levels of measurement there are nominal, ordinal, interval, and ratio scale variables that allow for different mathematical operations. While these levels have been presented to me in such ...
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Is there a statistical analogue of the quantum mechanical tradeoff between information gain and system disturbance?

Wikipedia defines a weak measurement: In quantum mechanics (and computation & information), weak measurements are a type of quantum measurement that results in an observer obtaining very little ...
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error on single measurement from long term data set

I have a data set with a few hundred measurements of the same standard. I also have a single measurement of an unknown using identical methods. If I assume that the error of both types of measurement ...
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Analyse measurement data with machine learning?

I am frequently receiving measurement data of a particular shape. The data come from a measurement and look roughly like this: https://en.wikipedia.org/wiki/Spreading_resistance_profiling#/media/File:...
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Calculating uncertainties in low stats radioactive decay data (Poisson Distribution)

Info: I have a data set of radioactive decays in 15s (to clarify, each point is just the number of counts in the last 15s, as opposed to the cumulative number of decays - since there is 3s of the ...
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How does one account for uncertainty in the independent variable when calculating the uncertainty of a fit

I am calibrating on sensor to another, measuring the same unit (temperature), over a range of values. The independent variable (accurate sensor) has a known uncertainty from a calibration sheet. I can ...
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Calculate effort impact score by weighting user complexity ratings

For every project we have a number of "Assets" associated with it. For one of our teams this drives all of their work. There are two type of Assets: Customised and Templatised. With ...
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Objective measures in Factor Analysis

I am considering developing a questionnaire (to be validated) whose scales could include both self-reported subjective measures and objective measurements. Does it make sense to use factor analysis to ...
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Can ratio data have negative values?

I get the concept of a "true zero" value, but I'm not sure why this implies that there cannot be any negative values—at least that's what most sources say that I found only, with only few ...
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How do I measure the performance of a model when only partial ordering matters?

I have a number of input data points $\{ x_0, x_1, \ldots, x_n \}$ and their corresponding outputs $\{ y_0, y_1, \ldots, y_n \}$. I also have two models $f, g : X \rightarrow Y$ that seek to estimate ...
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The difference between Index and Indicator

I am investigating the topic of Visual Pollution in my city, and have established some indicators such as Number of Visible Waste Bins and others but now, I am interested in building a single number ...
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Comparing Dissimilar Survey Questions

I am hoping to gain some insight on the most responsible way to fulfill a request at my place of work. I have been asked to show a quantifiable improvement year-over-year, by comparing apples and ...
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Finding most likely permutation

[Hoping that this is the right Stackexchange site; inspired from a true story seen at work] Joe has a measuring instrument and $n$ objects to be measured (say, a scale and $n$ weights). He measures ...
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Statistic for measuring the magnitude of bimodality in a distribution?

Here are some distributions of US political views by industry: After observing their mostly bimodal nature, I would like to measure the degree of bimodality in each of the distributions for the ...
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Controlling for Exam Change in Regression Model?

I am analyzing exam data collected from participants who applied to an academic program. The data was collected from 2014-2018, and applicants only took the exam once when applying to the program (...
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What are the statistical drawbacks of my naive and simple approach to discarding outliers?

I'm trying to measure and compare the performance of some computer programs. The simplest idea that comes to mind is to time, say, 10 runs in a row and present the arithmetic mean of the 10 timings as ...
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(Apparently) Different Definitions of Statistical Independence

I am reading John Mandel's book " The Statitical Analysis of Experimental Data). In it, in Ch 5, p. 52, he describes Statistical Independence of two RVs $X,Y$ in terms of independence in the ...
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how to interpret no change in chi square value in measurement invariance analysis, using lavaan

Currently I am using lavaan R package to do some measurement invariance analyses. One warning that I get confuses me a little bit: ...
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Intervention analysis

I'm really struggling to figure out how to construct a model here. Basically what I'm trying to measure is if a school endorsing a statement causes that school to change their policies. I have data on ...
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How to test if two methods of measurement are consistent?

I am measuring (the same) property of of 20 different objects. To measure this property I have two methods at my disposal. Which statistical test should I use to determine whether these two methods ...
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What does "at least ordinal" mean?

When the assumptions of a statistical test state that "the measurement scale should be at least ordinal", what does that mean?
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What level of measurement can I use to compare a student's different test scores?

Let's say a student takes multiple different tests. I get a percentage for each of the test scores (the tests have a different amount of multiple choice questions, and the multiple choice questions ...
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Imputing data using covariance?

Suppose I have some samples of sensor data, where each row has ten measurements from various sensors. And suppose I know what the covariances are among these sensor measurements. Are there any ...
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Using two sensors instead of one: Statistically meaningful?

We are using resp. manufacturing a certain device which measures, among others, the humidity of liquids. I got asked by a colleague if it makes sense to use two sensors instead of one (which a ...
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Does rounding violate the restrictions of an interval scale?

I'm currently working with questionnaire data from the NASA TLX. It uses a graphical rating scale with 100 equally spaced data points, broken up by 21 ticks, leaving intervals of 5. Its manual (p. 4) ...
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Estimating the actual distance by using a series of measurements in between

An object is moving along a single axis, back and forth. We take $N$ snapshots of the object. For all pairs of snapshot positions $i$ and $j$, we can make signed measurements of distance $x_{i,j} = -...
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What kind of a measurement variable are these?

Can anyone please explain what kind of a measurement variable these are? Facebook Pictures - I feel that these should be nominal but if there is a date stamp on the images, then it would be ordinal. ...
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What are some "nice" properties a "similarity index" should have?

I am reading a book that talks about how to construct a similarity index operating on a probability vector $\mathbf{p}=(p_1,...,p_k)$ to describe how similar its elements are. In my book, indexes of ...
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Measuring true value in an interval accounting for contributions from neighboring intervals

Suppose I have a record of every purchase of food made in 2019 and 2020 and I want to answer the question: how much did I spend on food in March/April/May in those two years (to see how much I'm ...
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How many days should I measure a variable to get a good estimate of 'average' behavior?

I have data for individuals, spread over a number of days. My dataset is very large: it covers way more days than what is typically feasible to collect. I want to use this to create a 'benchmark' of ...
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How to compare inter-rater reliability between two time points?

We have two sets of raters judge the same items before and after a training, resulting in an ICC and kappa value for each time point (pre- and post-training). How would you statistically compare pre- ...
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