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Questions tagged [measurement]

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

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Measurement invariance across groups and time

I want to run a multi-group longitudinal model. Based on prior invariance testing, I can assume scalar invariance across groups and time. So is it appropriate to have both the same intercepts across ...
JoMo's user avatar
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3 votes
1 answer
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How to improve testing method B, if Bland-Altman analysis show a near-perfect correlation between the difference and the mean between method A and B?

I have two sets of measurements (two different methods), A and B. Correlation between the measurements is only modest. Therefore, I wondered whether there is some inherent bias in (one or both) of ...
pishcotec_a's user avatar
2 votes
1 answer
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Why is reliability a ratio of true score variance to total score variance, instead of the ratio of true score to total score?

Reliability is given by: $r_{xx} = \frac{Var(T)}{Var(X)}$ where $T$ is the true score and $X$ is the total score. Why isn't reliability simply: $r_{xx} = \frac{T}{X}$ where $T$ would be a sum of all ...
J. Doe's user avatar
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Dry skull vs live skull measurement adjustments

I am working on a dataset that has dry skull measurements from a museum's collection (twice as many samples) or a live specimen (less common). As you can imagine, the live specimen are on average a ...
KellyForrester's user avatar
4 votes
1 answer
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How to detect a plateau at the end of a short time series?

In exercise testing (spiroergometry), participants' oxygen uptake is measured continuously while they engange in physical exercise that progressively intensifies. The measurements are taken at regular ...
COOLSerdash's user avatar
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CFA Measurement Invariance - can weak invariance be significant with the configural but not strong invariance? [closed]

I am a newbie here. I searched through the forum but did not find similar questions, so I hope someone who is proficient with SEM / lavaan can help out. I am using R lavaan and semTools to perform ...
zstats's user avatar
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2 votes
2 answers
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How to compare distributions if some data maxed out instrument/measurement?

I am comparing the distributions for the strength of two part designs. The test equipment maxes out at 300 units. The 300 units is an arbitrary limit of the equipment and does not represent a ...
AlexR's user avatar
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Does measurement invariance analysis assume equal latent scores across groups?

I have completed a measurement invariance analysis comparing high-school aged boys to high-school aged girls on a measure of depression. The results suggest that scores are not (scalar) invariant; ...
ila's user avatar
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What is F1 Score for this diagram?

I have this Venn chart that represent a dataset prediction of Identifying if our products are classified as "A41" standard or not The Blue Circle represents a Machine Learning Model ...
asmgx's user avatar
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4 votes
2 answers
254 views

Is there multi-variate generalized MAPE(Mean Absolute Percentage Error)

The MAPE could be employed in the context of regression problem and is defined by $$ MAPE := \frac{1}{n} \sum_{t=1}^{n} \left| \frac{y_{t} - \hat{y}_{t}}{y_{t}} \right| $$ where $y_{t}$ is target ...
Ryu Dae Sick's user avatar
2 votes
1 answer
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Response style as an alternative explanation for latent mean differences under scalar invariance?

I established scalar measurement invariance for a two-group CFA. The output from my final model showed that the latent mean in group 1 is lower than the latent mean in group 2. Can this difference in ...
user321797's user avatar
3 votes
3 answers
163 views

What is the (logical) relationship between an measurement instrument's validity and responsiveness?

The three major criteria for the quality of a measurement instrument are validity, reliability, and responsiveness. I understand validity and reliability, but I have trouble understanding the need to ...
Enuff's user avatar
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4 votes
2 answers
71 views

Is there a standard measurement of 2-dimensional precision?

Suppose a gun is fired at the bullseye of a target a specific number of times. Ignoring the accuracy (e.g. all the shots are well to the left and above the bullseye), is there a standard way of ...
Ray Butterworth's user avatar
6 votes
4 answers
1k views

"Decade" variable ranging over 130 years - Can I treat this as continuous? I've seen it done with 8pt scales...but it doesn't past the smell test

My dataset includes "decade founded" but not "year founded" for organizations. I need to include some "maturity" variable in the model. Decade is the best I have. The ...
user398893's user avatar
6 votes
1 answer
283 views

How can I calculate a relative measure of change for data series that can include zero?

I have a series of data points representing the number of OKs for a test. For each data point, I want to calculate by how much its value changed compared to the preceding value, and I need this ...
Mr Kartofel's user avatar
2 votes
2 answers
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Is it valid to take the midpoint of discrete outcome variables that express a range e.g. (1-20%, 21-40%) then calculate the mean of those midpoints?

I work in a health service and have a PhD student who was told by my boss (her primary supervisor) to measure clinicians' responses concerning what proportion of their clients had a certain condition ...
llewmills's user avatar
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Creating Correlation Matrix Tables with multiple variables within one measurement

trying my luck here since no one in my surroundings has worked with SPSS before and I am also clearly a newbie to SPSS and statistics. For my master degree I am researching possible correlations/a ...
Bettina's user avatar
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1 answer
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Normalised versus true racing times as DV for a learning experiment?

I have a question about using ratios as variables in alpine ski racing research. We want to compare skiers' performance on different days, but snow conditions affect the results. To address this, we ...
Cmagelssen's user avatar
2 votes
0 answers
34 views

Best way of determining how unique an inspector's ratings are compared to the average inspector

Noob question. I have a full population of every inspector rating for all items being rated. Each inspector has inspected a subset of the items and given them a rating, but different inspectors have ...
inspecting_inspectors's user avatar
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Adding a confidence interval to deal with noisy measurements

I have a formula and I am not sure how the author of this paper got to that formula. Im working on an algorithm that can filter out ground points from a Point cloud. The author describes the following ...
Okan's user avatar
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8 votes
1 answer
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How valid is the use of bootstrapping in my case?

I am currently working on the analysis of measurement data and have the problem of obvious non-normal data. Since most methods I want to use require normality (especially statistical process control ...
Krautsultan's user avatar
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1 answer
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Is ceiling effect mitigated by standardisation, renorming or combining with other indicators?

I have a psychological test that consist of a set of binary items. It has a noticeable ceiling effect in the sum scores (essentially, a majority of participants get most items correct). I also see ...
FredrikH-R's user avatar
2 votes
1 answer
91 views

BMI is calculated from two other measurements, so does it need adjusting for multiple comparisons?

If BMI is calculated from measures of patient height as well has weight, do statistical tests and resulting p values around BMI changes need adjusting for multiple comparisons? I.e. Two tests were ...
holmes's user avatar
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Very Basic Question - Propagation of Error and Fold Changes in Medicine

Say you have measured three conditions (x, y, and z) together and at three separate times (three replicates). These raw values are normally distributed and in a linear space. You use those three ...
JebidiahSpringfield's user avatar
5 votes
1 answer
91 views

What's the standard deviation of the difference between randomly paired data?

Assume that we want to compare the agreement of two methods of measuring blood pressure (e.g. a machine and a sphygmomanometer). In their paper, Preiss & Fisher (2008) discuss the standard ...
COOLSerdash's user avatar
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Just passing through: Estimating the probability that a changing quantity will pass through some value within a time interval?

Suppose I have a quantity that is measured periodically, that is continuous in the following sense: In order for the quantity x to move from x=a to x=b, x must pass through all the values between a ...
andrewH's user avatar
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Development of an adaptive scale

I need your help with a problem that I noticed and I don't know the solution (I am not from statistics). In sum, I would like to create a measurement instrument that is adaptive in that respondents ...
Larissa Becker's user avatar
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0 answers
21 views

Using items with different numbers of response categories across time points in longitudinal modeling

I'm doing a cross-lagged panel modeling for three time points. For one specific construct of interest, I have three items that were used for across three time points, but the number of items used for ...
hakim's user avatar
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3 votes
2 answers
390 views

In measurement invariance testing, how can one differentiate between differences in response styles and differences in latent means?

I am trying to establish measurement invariance between two groups on a depression measure: high-school aged boys and high-school aged girls. Though my entire sample reports elevated depression ...
ila's user avatar
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How to estimate variance when measuring fluctuating variable that never settles?

I am supposed the investigate viscosity related phenomena in water flow through a horizontal pipe, connected to a water tank at one end, and with clear opening on the other. Mounted in the middle is ...
This-name-will-do-nicely's user avatar
1 vote
0 answers
32 views

Detection limit for a drop in speed, due to stopping between measurements

Assume that a device is traveling at a constant expected speed $\mu$, subject to random variation with standard deviation $\sigma$, for a measurement period of duration $t$. Then the expected travel ...
shadowtalker's user avatar
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1 vote
1 answer
514 views

How to determine sample size for non-normal distributed data with continuous variables?

TLDR: I need to determine the minimum sample size for measuring the energy consumption of code. Hello, I'm trying to determine how many samples (N) I need in an experiment to be confident that my ...
Jamie Baldwin Pedersen's user avatar
1 vote
0 answers
16 views

How to treat data of one parameter measured with two same devices that show slight differences in averge [closed]

I have measured one parameter with two identical devices. Unfortunately one device shows higher values on average. Also maximum and minimum of the values differ by exactly the same value like the ...
Lara's user avatar
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1 vote
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Measurement of indipendent variables for binary logistic regression

I want to run a binary logistic regression to understanding (modeling) factors affecting nest-site selection in a bird species..I measured 32 presence points and 64 absence points. Instead of ...
Mostafa Ahmadi's user avatar
1 vote
1 answer
237 views

Do ordering and equal distances imply interval scale?

Variables measured on an ordinal scale have an order but the distance between levels has not to be 'equal'. In case distances would be equal, does this imply the variable is measured on an interval ...
user378171's user avatar
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0 answers
32 views

Are summary statistics of variables interval or ratio?

Would variables that are derived from other variables via summary statistics (e.g., mean, mode, standard deviation) be classified as interval or ratio type? Or neither?
keezar's user avatar
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How should I operationalize my variables?

I am trying to find out whether the regime type of states signing international cooperation agreements influence the design of the agreement, more specifically whether the regime type of the members ...
EmStaLo's user avatar
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1 vote
0 answers
75 views

Discrimination index or item-test correlation?

The discrimination of an item can be calculated as: $$D = \frac {K_h-K_l}{N}$$ Where $K_h$ is the number of correct responses from the high scoring group, $K_l$ from the lowest scoring group (top and ...
gabriel's user avatar
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-1 votes
1 answer
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what statistic test to use for measuring the differences between the same individual

I am planning to conduct a study to measure the length of the left and right ear on the same individual. I am stumped on which test should i be using and i would be glad if anyone can set me on the ...
stumped's user avatar
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1 answer
30 views

Creating equation for Customer Loyalty Score

Goal is to establish a loyalty score for a customers of particular TV Brand. Listed below are some factors that I think should logically affect the score. Features of a Loyalty Score Loyal Customer ...
Rajasimhan's user avatar
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0 answers
30 views

Can I sum random variables and get a semantically useful result?

I repeatedly measure two values, $a$ and $b$. Measurement $a$ correlates with two real values $X$ and $Y$. For measurement $b$ the correlation with value $Y$ should be smaller, maybe even 0 while ...
Skusku's user avatar
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1 vote
1 answer
99 views

Factor analysis between two measures with different age range

is it totally meaningless or impossible to do factor analysis between two measures with different age ranges? For example, I want to test if two personality measures are testing the same underlying ...
IvesDragonfly's user avatar
1 vote
0 answers
19 views

Determine drift

I would like to determine potential drift in the data/device. Is there a general acknowledged procedure and/or method to do so? I know how to visually "detect" a drift but I would like to ...
Ben's user avatar
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2 votes
2 answers
287 views

Data simulation in R for Measurement invariance

I am trying to generate random data for an analysis of Measurement invariance. I will be looking at a one-factor model for two groups with 4 variables each. I would need to generate a sample where I ...
Blapo's user avatar
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1 vote
2 answers
92 views

Are there better measures of entropy

Related question here I am trying to measure the uniformity of multimodal distributions and am looking into using entropy. I would like a measure of entropy that is higher for the first distribution ...
Tom Huntington's user avatar
1 vote
1 answer
67 views

What is the level of measurement of my dependent variable?

For my master thesis I conducted an online experiment where participants had to conduct a shopping task where they were provided with a local and a non-local product three times in a row. So for three ...
carina's user avatar
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2 votes
1 answer
610 views

Using Factor Analysis for Items on Different Scales [closed]

I have a quick question about factor analysis from different scales. Is it advisable to use, conjunctly, items from different measures? For example, if I am interested in doing EFA in the context of ...
JerBear's user avatar
  • 61
3 votes
1 answer
61 views

Categorical or continuous? I can't decide

This may seem like a simple question, but it would be helpful to know others' opinions. I am trying to determine the effect of distance on growth. Growth is a continuous variable (i.e. 2.46cm). ...
EllaB96's user avatar
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0 votes
0 answers
22 views

How does measurement invariance work with demographic variables?

I am running an analysis that includes an argument for measurement invariance which can be set as true or false. If true, item-response probabilities are constrained to be equal across groups. When I ...
user360879's user avatar
0 votes
0 answers
34 views

Sample size for medical device which provides repeated measurements

I have a medical device which provides continuous measurements of a substance in the body (X) over time. There is currently an established reference standard (Y) which measures the same substance but ...
Deng-guy's user avatar

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