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Questions tagged [measurement]

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

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Scale invariant comparisons of two sets of vectors

I am dealing with the following problem. Let A and B represent two sets of real-valued vectors. The vectors are of the same dimension, yet the sets contain different number of vectors. I am looking ...
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How significant are the results of my classifier?

I have seen this and this questions, but all of them are about accuracy. I have 5 different binary classifiers on imbalanced datasets (most of the samples are negative). I need to prove that one of ...
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1answer
28 views

Statistical uncertainty in average of continuous variable, where values are not expected to be the same

I have been trying to understand statistical uncertainties on measurements made, I have found many partial sources, but they seem to either deal with simply counting whether something happened or not ...
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1answer
31 views

What type of data is this? Nominal, ordinal, interval, ratio

If you were to do a survey and ask, “how many people have lived in a town for less than 2 years, 2-9 years or greater than 9 years?” Would this be considered nominal, ordinal, interval or ratio?
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Meaningful statistics for difference in measurements between 2 of the same device

When looking at something like temperature data from 2 thermometers they don't record the exact same values. What would be some meaningful statistics to look at when comparing multiple sets of ...
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Metrics for comparing a multi-class model vs. a multi-label model?

The dataset is a multi-label dataset, where each item can have more than one labels. I first trained a multi-class classifier by randomly select the label for each item at each iteration, and ...
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19 views

measuring constant value

I'm taking multiple measurements of the same constant value. The measurements are noisy (lots of outliers) and I can take lots of them, more than I can store. How would I approximate the true value? ...
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Combined uncertainity given probability measurement belongs to one of two classes

I have two classes of measurements $A$ and $B$ characterized by different uncertainty distributions. I also have a probability $P_A$ that a given measurement belongs to class A and not B ($P_A = 1 - ...
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4 views

Similarity between observations and an ideal trend

I have a series of well known data showing, for example, the average weight by age in Europe. Let's say yesterday I called a lot of people and I asked for their age and weight. The data coming from ...
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1answer
32 views

Comparison of measurement methods

I have three sets of measurements (A, B, and C) of the same thing. One of them is the gold standard (say A). I want to determine if B and C overestimate or underestimate the true measurement (which is ...
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After conducting an EFA, how to score a factor for new participants using its constituting variables?

I study psychology, and I'm learning EFA (again autodidactically -_- bloody middle east).. So I hope you help me with this naive question Scenario I have a questionnaire made, and I was able to ...
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Different conditions on data measurement for ml

Is it possible to train a prediction model (on my case classifier with four classes) between data taken on different conditions? To be more specific I have two data sets and for my task I am allowed ...
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1answer
24 views

Valid way of determining spread of data

I’m trying to determine a valid method for quantifying the maximum spread of values I can statistically expect to see. I’ve collected 12 sensor values from 12 different sensors. I’ve calculated the ...
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38 views

Fixed-Delay Kalman smoother with/without augmented measurements

There are several algorithms regarding fixed-lag Kalman smoothing. In most cases, an augmented state vector is defined in which the elements are the current and delays of the original state vector. ...
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59 views

Must MSA be re-performed after annual instrument calibration?

I'm working in an automotive company that must follow IATF (International Automotive Task Force) requirements. I administrate a test-bench that performs radio frequency tests using an appropriate ...
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Measurement theory and sample size calculation for multivariate testing

Let $\mathbf{Y}$ be a vector of independent, normally-distributed random variables. Let $S_1$, $S_2$ and $S_3$ be three non-overlapping samples of sizes $N_1$, $N_2$ and $N_3$, respectively. Let $M_A$ ...
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25 views

How do I weigh values by their relative frequency and then get an average?

Suppose I have three values that were measured repeatedly in a study. The conditions imply that the values should be close to each other, i.e. ideally three times the same value. The measured ...
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1answer
26 views

How to handle measurement inaccuracy? [improved]

This is based on my old question but the question was too confusing. I've tried to make it clearer this time. This is the kind of data we're dealing with: ...
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2answers
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Measure spread of non normal distribution?

I have sentiment data for customer reviews drawn from a larger population of reviews. Each product has a number of customer reviews. Each review has a sentiment (opinion/feeling) between 0 and 1 where ...
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how to quantify the patterns of multivariate distribution (e.g. clustered in the center vs. spread out all over the place)?

I am wondering if there exists a well-established way to quantify such patterns (please see the graph)? I guess there should be multiple ways to quantify it or multiple aspects that can be quantified. ...
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11 views

Can we calculate the best possible test set loss given the information in the training set?

Given a training set and a test set for machine learning, I am wondering if I can somehow measure if the information to predict the labels of the test set correctly is present in the training set. In ...
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1answer
41 views

Calculation of relative performance gain

I want to measure the improvement of students using exam marks of semester 1 to semester 3. The following detail should be considered when calculating the measure; If Student A get 30 (sem 1) and 50 (...
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458 views

Can a ratio level variable have negative values?

According to Stevens (1946) ratio level variables require an absolute zero. The implication, I believe, is that 0 = an absence of the thing being measured. As such, can ratio level scales have ...
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Comparability of the dependent variable measure over time

I need to estimate the effect of several educational policies that were implemented over 20 years on schools performance. School performance is measured as percentage of pupils who pass the exam at ...
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21 views

Combining distributions

I have a ruler and a set of poles $S$. My ruler is not perfect, so a length measurement of one pole yields in fact a sample of a probability distribution (e.g. natural scientists usually find normal ...
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1answer
201 views

Conversion of Interval data to ordinal data

I recently learned about Level of measurements and I am really confused in this MCQ where I think the right answer is a and d both. Lets say the three participants finished in a race in 45 seconds,35 ...
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Alternative measurement for Cross Entropy Loss than accuracy when using soft labeling?

Suppose one has multi-class ($n>2$) data, where class labels are soft, e.g. two samples of for 3-classed data might look like: ...
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How do you calculate interrater reliability for multiple items?

I have responses rated on 12 binary categories, treating the categories as separate items on the same measure. There are 10 raters, so Fleiss's Kappa seems appropriate. How would you compute ...
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39 views

Correlation coefficient when independent variable is uncertain

I have a model, which I would like to validate against observations. Typically, I would make a scatterplot of the observations vs my model outputs, and calculate the correlation coefficient (among ...
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27 views

How to measure metric baseline?

During planning of an online A/B test, after we choose a success metric, we need to estimate the sample size required to detect a minimum effect. Usually this formula[1] is used: $n = 16 \frac{σ^2}{δ^...
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2answers
63 views

Does the interval/ratio distinction ever matter?

Statistical methods vary according to the measurement levels of variables, and it can make a difference if variables are classified as nominal, ordinal, or interval/ratio. But I've never seen any ...
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38 views

How to determine which event happens more often?

I am writing a program that measures how many clock cycles a certain piece of code takes. This varies a lot as a result of all kinds of unknown influences and is by no means a normal distribution; for ...
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0answers
11 views

Proper way to assess median failure distance in the presence of censoring

I would like to measure the median distance at which a material fails when it is stretched. At first pass, this sounds trivial and there is a simple version of this by which I pull a material until ...
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30 views

Measuring emotion differentiation on a within-person level.

To measure emotion differentiation, which refers to the precision of an individual to accurately describe and distinguish between different emotional states, many studies have used a between-person ...
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Ordinal or Interval Level of Measurement?

If we have a score of number of students in a kindergarden, which goes "one, two, three, four, five, six and more", is this variable interval or ordinal? The differences between them are exact, yet ...
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Measuring Distances and Subsequent Analysis

I am measuring 24 colour panels using 4 different devices. I know the ground truth of the 24 colours - they are a MacBeth colour chart. Measuring the 24 colours yields a matrix of measurements (24 x ...
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1answer
52 views

What statistic to use to assess repeatability of measurement [closed]

I want to assess the repeatability of a measurement device. Let's say I have made three measurement with the same device under the same conditions. What statistic is useful for assessing the ...
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1answer
173 views

Examples of Change of baseline vs Final values

I'm learning how to perform a meta-analysis from the Cochrane handbook: http://handbook-5-1.cochrane.org/chapter_7/7_7_3_1_post_intervention_versus_change_from_baseline.htm Here they talk about the ...
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Calculating/Averaging/Aggregating Effect Size Across Multiple Measurements

What is the standard practice for calculating a total effect size (using Cohen's d) across multiple measurements in one study? Do you calculate the effect size for each measurement and then take the ...
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1answer
71 views

Management Objectives with no upper limit

Imagine I am working for a "fictional" company and they have given me a list of objectives to measure their managers' performance. An example of how they are measuring them is as follows: ...
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1answer
219 views

Which is the correct F-beta-measure scoring formula?

I have found differing formulas to calculate the $Fbeta$ score, which changes the weight (influence) of $PPV$ ($Precision$) or $TPR$ ($Recall$) from the default of equality (i.e. $0.5$). For example: ...
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Assessment of risk score for prediction of known outcome

I have a population where a conventional risk score and a binary outcome are known. I am interested in assessing an alternative risk score, but I will need to do a detailed review of cases to measure ...
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1answer
67 views

Why is it that interval scales allow for addition/subtraction, but not multiplication/division?

Why is it that interval scales allow for addition/subtraction, but not multiplication/division? If multiplication is just repeated addition (ditto for subtraction/division), why is it that interval ...
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1answer
34 views

Level of Measurement

I am a Math Phd student and a Teaching Assistant for Statistics in Psychology Deparment. The problem I have is to determine the level of measurement. Let me first present the question: Assume that ...
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2answers
65 views

Appropriate error measure

Statistics is not realy my field of knowlegde but I am trying to find an answer for the following question: Many cities nowadays have a bike share system. Suppose you were asked to predict how many ...
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1answer
91 views

Measure of closeness to one of two points [closed]

There is a finite set $W$ with two distinguished points $A$ and $B$. There are two measures of closeness of a given $X\in W$ to $A$ and $B$, respectively, denoted by $\rho_A$ and $\rho_B$. In ...
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1answer
22 views

Measuring the aggregate … “we” vs “I”

I am involved with a project measuring organizational behavior. My colleagues are split in terms of measures reading "we feel..." vs "I feel..." as the subject of the measurement. Personally, I ...
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1answer
57 views

How Can We Measure Error In Bits of Information?

Curve fitting, using conventional measures of error, such as LSE (Least Squares Estimation), cannot include the complexity of the formula because the complexity of the formula must be measured in bits ...
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1answer
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Constructing an index: is it necessary to standardize? Which is the best solution?

I'm constructing an index made by the sum of three variables, which all vary in the range [0,1] (as they have been divided by their theoretical maximum). Depending on the sample analyzed, it is not ...
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200 views

How to measure consistency of measurement over time

Let's say I have multiple wine experts who rank set of wines over time. To put it formally, I have n experts, m wines in the set and c measurements. Measurement is a matrix with n rows and m columns, ...