Questions tagged [measurement]

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

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7 views

One measuring equipment with two different resolutions: should the MSA Type 1 be splitted into two seperate studies?

I want to do an MSA Type 1 (capability analysis prior to it's use) for a scale which has two different resolutions: from 0-5 it is 0.01 and from 5-10 it is 0.1. I am wondering if I should in this case ...
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comparison between two measurement devices

I have two measurement devices accelerometer A and B. The measurement is the step time of a person walking in a corridor. A is the gold standard. I want to check the validity and reliability of B. how ...
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161 views

How can I know if two distributions have the same mean and standard deviation?

I have some cells which fluorescence and I can detect their fluorescence. So for each cell I get a number N that says how much light it emitted. I also have two ...
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10 views

Measuring standard/formula when we know length, mean, highest and lowest values of a set

This is probably a basic statistics question, sorry about that. I have sets of data that I wanna compare. Each set has a list of values from which I know the length, mean, highest and lowest values ...
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23 views

How do I propagate asymmetric error/confidence intervals? [closed]

Assume that I have two measurements with asymmetric error, $X^a_b$ and $Y^c_d$, and I want to find $Z^e_f = X^a_b + Y^c_d$. How do I find Z? The type of answer I'm looking for is of the form : $e = ...
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1answer
57 views

Is median or mean more accurate for technical replicates of assay (small n)?

If I want to improve the precision of the results of an assay by averaging a few repeat measurements of each sample, when the random error is generally normally distributed but occasional outliers ...
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8 views

Measure Tire Tread Depth

Is it possible to measure tire tread through image processing, taken from a smartphone? And does anyone have the idea on determining the tire life based on the depth? I'm planning to develop a mobile ...
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2answers
97 views

Ratio Measurement Scale and Absolute Zero

Levels of measurement are: Nominal, ordinal, interval and ratio. What happens when the absolute zero of a data set using the ratio scale is a negative number? I.E when the absolute zero is -25,000? ...
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28 views

Modeling background noise with a half normal distribution

I'm working with radiation measurement data and have background noise data with $(\mu, \sigma)$ < 1 and all background measurement values >= 0. If I wanted to approximate/model this noise, would a ...
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1answer
11 views

How to compare two, time based, measurements of the same object

I have 2 rounds of measurements from a set of 10 capacitors. The measurements are with respect to frequency and are all measured at the same 200 frequencies between 1 kHz and 5 MHz. The data is not ...
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1answer
36 views

Measured data not normalized - but should it be?

I'm analyzing some data at the moment and I just stumbled over the situation that a part of itseems to be not normalized. Background: Several gas sensors were measured and the value of a resistor is ...
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Study variances between devices of the same type in order to make a statement about its goodness

I have 2x7 devices with a measurement series over time. It is about studying gas sensors. Therefore, following paramaters are given: ...
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Does Fisher Information quantify precision? [duplicate]

Looking at perspective from estimating the actual value from a set of data measured by the instrument. Does Fisher information just quantify the precision of the measurement? What does it say about ...
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1answer
29 views

Comparing observed binomial data with data simulated from a physical model

I have ~20 datasets which contain data that I assume is, conditional on a single variable, binomially distributed. I have built a physical model of the process generating the data and can simulate ...
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1answer
108 views

Why are we interested in top-n accuracy?

I know the definition of top-n accuracy: [1] What is the definition of Top-n accuracy? My question is, why do we even care for this? A short answer could be to compare different models in various ...
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20 views

Identify difficult parameter to measure [closed]

I am using different tools to measure x on some objects. The tools were tested on a small set of objects for which the true x is known. And so the predicted values were found to not be accurate for ...
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34 views

How to get one composite score to represent a MIMIC factor (including both formative variables and reflective indicators)

I have a MIMIC model where the latent variable of interest has both formative causes and reflective indicators (as depicted in the figure). My question is: is there a way to get one composite score ...
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22 views

Does reliability of measurement affect the minimal sample size required?

The following calculator (like many of its kind) uses a number of variables to determine an adequate (and importantly, representative) sample size: https://www.calculator.net/sample-size-calculator....
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1answer
53 views

If I take mean of uncertain observations what happens to SD of the observations?

I have some observations, each with an accompanying standard deviation (shown here as error bars): I want to make a summarised plot of this data by taking mean of all observations for a given X value,...
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2answers
70 views

Is displacement an interval or ratio data?

Distance Has natural zero point (no distance no travel). You cannot travel a negative distance. 2m to 4m is twice the distance. Hence, distance is a ratio data. Displacement Has a zero point (...
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Youden's J statistic can be negative but it is said to be between 0 and 1

J = (true_positives x true_negatives - false_positives x false_negatives) / (positives x negatives) where positives and negatives are the number of real positive and real negative samples. ...
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20 views

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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15 views

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
40 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
47 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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67 views

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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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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6 views

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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6 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
37 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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9 views

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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17 views

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
49 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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78 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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29 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
29 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
206 views

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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1answer
121 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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1answer
890 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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26 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
401 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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140 views

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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660 views

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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2answers
98 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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39 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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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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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 ...