The measurement tag has no wiki summary.
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26 views
How many measurements should be done?
I am measuring time of a computer operation. The operation should run roughly same time each time I measure it. How many times should I measure it to get good average and standard deviation?
...
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16 views
Covariance of function uncertainty, why (J^T)*S*J? [duplicate]
As I understand it; to get the uncertainty of a function that is based on some measurements, the derivative of this function with respect to this measurment has to be calculated, and multiplied by ...
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20 views
Measuring Diversity - Blau's Index + Adding Weighting
I would like to use Blau's Diversity Index for the following Data:
Functional Diversity in Partners (based on 4 functions = 4 categories)
Industry Diversity in Partners (based on SIC codes & 5 ...
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20 views
how to report that we use linking item response score in dissertation?
I refer many thesis both PhD and Masters,but none reported on this matter where the
situation that they use one questionnaire to measure a variable, however the questionnaire have two version that ...
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1answer
44 views
Can all methods made for certain level in measurement hierarchy used at all higher levels?
Let's say there's a measurement hierarchy for discrete variables, that looks like nominal (grade pass/fail) < ordinal (grade A/B/C) < interval (grade 90-100; 80-89; 70-79, etc). Hierarchy is ...
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39 views
Calibrating speed [closed]
I would like a correct official terminology for calibrating speed.
I work in calibration and we when calibrating our SIS instruments have to calibrate with two measuring sources, i.e.:- for ...
2
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1answer
72 views
interval or ratio?
I have a question about how to interpret some discrete data. Some are very easy, like the number of children in a household: that is a discrete and numerical, measured as a ratio variable.
Other ...
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0answers
31 views
Predict missing value(s) using existing measurement's data
I have a few measurements (6) with 13 different features (so I have more parameters than measurements).
Let's say I would have a new measurement with a few missing values, considering I have existing ...
2
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2answers
118 views
What do you call a measurement that's halfway between ordinal and interval?
Suppose you have a measurement $Y_i$. Now suppose that the differences between two measurements $\delta_{ij}=Y_i-Y_j$ are an ordinal measurement. From my understanding, $Y_i$ is more informative ...
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26 views
Statistical Model - question on the product measure for a non-parametrical model
A non-parametric statistical model can be defined as follows:
$$\{\Xi,\mathcal{B},\mathcal{P}\}$$
where $\Xi$ is the sample space, $\mathcal{B}$ is a $\sigma$-algebra and $\mathcal{P}$ is a ...
2
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0answers
49 views
Assessing the ability of two quantitative methods measuring the same thing
Suppose I have two scientific approaches to measuring the same physical quantity taking values between $[0,1]$. One (say method A) is generally accepted to be more accurate under certain conditions, ...
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1answer
63 views
How to evaluate a curve considering outliers?
I have data on runners who run marathons; for each runner I have their final times on a number of races. I would like to predict how fast they are running considering outliers i.e.
he's running ...
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1answer
50 views
Level of uncertainty when measuring a period of time?
I need to create a raw data table for my science experiment, but I'm unsure what the level of uncertainty would be when measuring days. How would I determine the level of uncertainty when measuring a ...
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1answer
188 views
Can statistics based on crude units of measure be improved?
I'm collecting online recipes in order to calculate average ingredient proportions for, say crepes or pastry. Most volume based units of measure in english recipes (cups, tablespoons, teaspoons) ...
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0answers
191 views
What helps (justification) to decide cut score/cutoff points for 5-point likert scale?
I am wondering what are the factors involved in deciding the cutoff value / cut score for 5-point likert scale from:
...
3
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5answers
275 views
Conversion between units of measurement
I have two different measuring instruments, A and B, both measure the same physical quantity but with different unit of measures: $u_A$ and $u_B$.
A is a reference instrument.
I measured a reference ...
1
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3answers
99 views
Can unsupervised evaluation measures for clustering replace a supervised evaluation measure?
Is it possible to have the same evaluation performances when comparing some clustering algorithms using many unsupervised evaluation measures instead of a supervised one ?
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0answers
162 views
When is appropriate to run a factor analysis at items level vs. scale level in a new questionnaire?
I am doing a research validating a new questionnaire, which has 156 items divided up in 12 scales. I have run a factor analysis at scale level, which gives me two nice constructs (consistent with ...
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2answers
602 views
Interpreting t-value as a measure of evidence
Came across an article on the web on "evaluation of training effectiveness". The author suggests that the "t-value" obtained from a "Paired t-test" conducted using pre-test and post test scores can ...
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2answers
213 views
What level of measurement is a factor score?
After doing a factor analysis, I decide to use that factor to test a hypothesis. However, I am not sure what data type of the Factor score the is (i.e., nominal , scale, etc.). Can I do a t-test or ...
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2answers
99 views
Exploratory factor analysis among items with different measurements
I intend to do an exploratory factor analysis among items that have different types of measurements: for example, some items have bounded scales (1-100%), some items take small and other large values ...
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1answer
85 views
Primitive length measurements
A measuring rod has length $u$ (for "unit") and a long object has length $x$. Suppose $u$ is laid end to end $i$ times and $x$ is laid end to end $j$ times. We want to observe whether $iu\ ...
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1answer
487 views
How can I align/synchronize two signals?
I'm doing some research into respiratory physiology but have come stuck at the analysis stage (should've paid more attention to my stats lectures).
I've collected two simultaneous measures of ...
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0answers
14 views
Analysing differences between two variables for the same people at one point in time? [duplicate]
Possible Duplicate:
What is the proper way to analyze discrete data?
I have data from a large scale survey. I am interested in analysing the differences between two variables. Both ...
3
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2answers
109 views
Experiment involving darts, how should I measure the response?
I'm conducting a project where I determine which factors (3 in total) contribute to the accuracy in which one would hit a dartboard. Each factor has two levels, low and high. For example, one of the ...
4
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2answers
176 views
How do I handle measurement error in sparse data?
Under-educated non-statistician seeks short-term relationship for very one-sided benefit.
System in question involves rocks and physical properties. Modelling bits of the earth typically means few ...
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3answers
117 views
Learning measurement uncertainty; could not find any online resources
I'm currently writing a lab report on Atwood's machine, and the gist of it is that $a=a_{g}\tfrac{\left ( m_{2}-m_{1} \right )}{\left ( m_{2}+m_{1} \right )}$.
We're holding $\left (m_{2}+m_{1} ...
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2answers
61 views
Inferring a likely full population from multinomial measurement or survey data
Assume that we have one or several multinomial samples (e.g., surveys) taken from our population. While inferring characteristics (such as mean values, correlation, ...) from a multinomial sample is a ...
3
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2answers
217 views
How to test if reading from two devices are significantly different?
I am trying to compare readings from an old flowmeter and a new digital flowmeter to find out if they are significantly different. With the new meter I did readings under different conditions eg. ...
4
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1answer
329 views
Evaluation measure of clustering (without having truth labels)
I'm clustering a set of data but I don't have truth document that allow me to evaluate the result of clustering (I have unlabelled data), so I can not use an external evaluation measure. In this case, ...
1
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1answer
57 views
Probability of a measurement under a continuous model
I may be measuring the length of a stick. I then want to see what is the probability of one measurement under a model.
When using a continuous model, the probability of a single number is zero:
$$
...
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1answer
3k views
Likert scale categories and composite scores
I have used the following Likert scale for a series of questions in a survey:
0 = Not Important
1 = Slightly Important
2 = Moderately Important
3 = Very Important
4 = Extremely Important
As I ...
3
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1answer
42 views
What is a good modern task load measurement?
I will be conducting an experiment during which I need to measure mental load.
After some research I decided on subjective measurements, as I can't obtain the equipment needed to attempt objective ...
3
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1answer
360 views
How to correctly describe measurement variation (over multiple repetitions)
Firstly, please forgive my lack of statistics knowledge, but I am hoping someone can clear up my misunderstandings.
I am taking a sample of a physical quantity, (for example: temperature). To take ...
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2answers
202 views
How do economists quantify black market operations?
I was doing a lot of research into organized crime in East Asia for a project as a favor to an author-friend of mine, and I noticed that there were noted economists and journalists who, in ...
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2answers
117 views
Goniometer data analysis
I am designing a health science experiment for uni and am focussing the study on measuring range of motion in a person's knee before and after they wear a copper bracelet. To measure the ROM, we are ...
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0answers
220 views
How to create a ratio distribution from samples?
Ok, let's try again. The context of the original question is given below, but perhaps it helps to focus on the statistical aspect to get an answer.
What I got is a number of measurements in unit t. ...
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1answer
38 views
Formula for comparing the youth of different groups?
For purely personal reasons, I recently tried to write a Ruby script that pulled information about various school rosters, counting the numbers of freshmen...seniors on the team and using that data to ...
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1answer
479 views
Are nominal attributes strict classifications and equivalent to enumerations in programming languages?
I've been looking random forest algorithms for text classification and referencing the Mahout random forest decision tree description. In it, there is a reference to two types of variables, nominal ...
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1answer
107 views
Assessing effect of intervention where aptitude tests used in pretest and posttest have some overlapping and some distinct items
In my research there is a pretest, and a treatment followed by a posttest.
The pre and the posttests are similar but not exactly the same. A few questions were changed between the pre and posttests ...
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2answers
77 views
Looking for a name for a “mean-influencing” statistic
I have been using a statistic to measure "influence" or some analogous concept in the following way:
First calculate the mean for a given sample, then calculate the mean for the given sample ...
6
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1answer
408 views
What is perplexity?
I came across term perplexity which refers to the log-averaged inverse probability on unseen data. Wikipedia article on perplexity doesnt give a intuitive meaning for the same. This perplexity measure ...
6
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1answer
77 views
Is there a classification of physical measurements according to their statistical distribution?
I am looking for a document or research articles classifying physical or chemical measurements (or perhaps better means of measurement) according to the reference statistical distribution and ...
1
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2answers
146 views
What's the difference between “measurement method” and “measurement procedure”?
The ISO VIM defines them as:
measurement method:
generic description of a logical organization of operations used in a
measurement.
measurement procedure: detailed description of a ...
2
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3answers
593 views
Measuring linear correlation of non-normally distributed variables
How can I measure linear correlation of non-normally distributed variables?
Pearson coefficient is not valid for non-normally distributed data, and Spearman's rho does not capture linear correlation.
...
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5answers
771 views
Best distance measure to use
Context
I have two sets of data that I want to compare. Each data element in both sets is a vector containing 22 angles (all between $-\pi$ and $\pi$). The angles relate to a given human pose ...
3
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2answers
138 views
What does averaging do for the noise level of my signal
We are measuring data with a high sample rate (20 kHz) and calculated a big standard error due to our system setup. Currently we are only interested in slow signals (in the order of Hz's) is it valid ...
2
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2answers
371 views
Measure of closeness
Given a list of numbers, is it possible to find out (or in other words, is there a statistical measure to tells the) the closeness of the numbers
(do note that i am not talking about correlation - ...
2
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1answer
191 views
How to estimate the likelihood function for random generator of three events?
I have a random events generator. I know in advance the set of event that can be generated (in my case I have only three possible events). The probabilities of the events are not known. I need to ...
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1answer
518 views
Data Augmentation Examples
I am looking for applied references to data augmentation (preferably with some written code). Either online references are books would be great.
I found this book online:
...
