Questions tagged [frequency]
The frequency measures the number of times an event occurs in a data set.
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How to calculate harmonic equations from a complex wave
I’m working through an online example that explains spectral analysis in R. Let’s say you have a complex wave:
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Scientific reporting of time-varying covariates at different time frequencies
Say I have the following model:
$$y_{it} = \gamma_i + \delta {T}_{it} + \zeta Z_{i(k)} + \epsilon_{it}$$
where $y$ is some outcome for household $i$ in month $t$. $\gamma_i$ denotes household fixed ...
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Which statistical test to compare frequencies across groups?
I am running an analysis in which I want identify if there are significant differences in the features that make up two groups: people that commit crimes against children and people that commit crimes ...
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Which Significance test to apply to compare number of occurences of multiple events across multiple groups?
Our dataset is composed of time-series data (recordings) collected for 18 different groups (test conditions G0 to G17). The number of recordings per group can vary (30-600). For each of these ...
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How do I decide the frequency of data capture for modeling?
I plan to capture data to predict energy consumption in a food processing plant. I want to capture production details such as how much each category of food is produced, what is the machine's output, ...
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How to model discrete bivariate probability distributions with a 'triangular' support?
I'm really at a loss as to what this is called, so please tell me if this is a duplicate and I'll be happy for the question to be deleted if that is the case (though I likely will still have follow-...
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LOCF and Reverse MIDAS Regression
I have a higher frequency time series as a target $y$ and lower frequency time series $X$ as predictors.
I have found this approach, which reverses MIDAS, which is usually used to model a low ...
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Arrange data so that two variables are linear
I have the following set of rainfall intensity data
and I want to make a compilation of the rainfall intensities above some practical minimum as shown in the figure below.
So the intensity and the ...
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Power spectral density and frequency of noise
I have a vector of 1280 000 data points, representing a bioelectrical signal (Evoked Potentials). It consists of 2500 stimuli and responses, and therefor has 2500 individual "signals". The ...
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Combining multiple columns in R to get frequency count? [closed]
I have incident data and for each incident, there are multiple individuals each with sex/age. The data looks something like this:
incident
person1
personl1sex
person1age
person2
person2sex
person2age
...
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What are the name of this distributions appeared on bitcoin trades data?
I have been playing with some bitcoin data that i download from binance API the data correspond to 1min klines there is 1 million of samples that start from 01/08/2020 to 01/02/2022
if i make a ...
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Why should the frequency of heads in a coin toss converge to anything at all?
Suppose we have any kind of coin. Why should the relative frequency of getting a heads converge to any value at all?
One answer is that this is simply what we empirically observe this to be the case, ...
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Likelihood that observed relative frequencies match a probability distribution
For this question, please assume probability distributions are discrete.
If I have $N$ data points ($x_1, x_2, ..., x_N$), and I want to know the likelihood that these samples came from a discrete ...
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Modelling seasonality by means of Fourier decomposition
I'm trying to model seasonality of a time-series by means of Fourier decomposition in order to model some yearly recurring patterns. The Fourier decomposition consists out of a few steps.
The time-...
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Occurrence certainty
I think the best way to ask this question is with a hypothetical situation. Let's say I have a sensor that measures on average one occurrence every 3 days with a standard deviation of about 4. I want ...
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Determining Frequency for Rankings based on their timeline
I have a dataset that reflects rankings for products over a long time period.
I do not know how the ranking represents sales, but my first assumption is that I can apply Zipf's Law. However, I don't ...
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How variability with different data densities could affect comparisons among environmental variables
I have several sets of data continually measured and recorded by instruments. The periods of record are 30+ years and the frequency of measurement can be every 5, 10, 15, or 30 minutes (288, 144. 96, ...
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How to specify frequency higher than months for time series
How do we set frequency if we have data with frequency that is higher than months in a time series?
If we use months, we can set frequency to 12, but for daily data ...
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How to compare the frequencies by multiple groups?
Here are my data. Each row represents a sample and different VAR mean different component.
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What does the y-axis in this Frequency vs Residuals graph mean?
(Asner et al 2013)
This is on a paper I'm reading, and I get the residuals part, but I'm not so sure on what the frequency means. Can someone please explain these graphs?
Please let me know if you ...
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Doubt around Covariance definition
Given the general definition of Covariance between two random variables $x$ and $y$:
\begin{equation*}
\text{Cov}(x,y)=\frac{1}{n}\sum_{i=1}^n(x_i-\bar{x})(y_i-\bar{y})
\end{equation*}
Does the above ...
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Dealing with zero cells in the psi frequency test
In Jayne's "Theory of Probability" book, he proposes the psi test of frequency as opposed to the more common chi-squared test. He demonstrates how the test deals better with low-expected ...
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Intervention Impact/time series for data with inconsistent frequencies
What can I do about time series analysis for data with extremely inconsistent frequencies? I am putting together a data set based off satellite imagery where, in some years, I can extract 3-4 data ...
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How compare relative frequencies between different sized groups (fish species)?
I have gathered data from a number of studies on presence / absence of fish species at 4 locations (let's call them A-D) with different proximity to a structure. I am interested in knowing how ...
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Comparing Term Frequencies in Corpora of Different Sizes
Relatively new to quantitative linguistics and still trying to get a foothold on a solid methodology.
I have two corpora: a "general use" American English corpus (enormous in size) and a ...
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Standard Notion of Limit for relative frequency to define probability
I am self studying probability theory and am reading the book:
Understanding Probability: Chance Rules in Everyday Life by Henk Tijms.
In second chapter he explains about what challenges relative ...
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How handle frequency data to make it comparable between different sized samples?
I have gathered data on presence / absence of objects at 4 different locations from a number of studies (12 to be exact).
I am interested in knowing how frequently each of these objects are recorded ...
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Given a distribution of the frequency of use of different materials in production orders, figure out how many top-used materials enter 98% of orders
I'm looking for help in a strategy for solving this. Tried just getting a ppf of the beta distribution, where q=98%, but I'm not sure I'm taking a right strategy altogether, because there is no data ...
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Selecting the method to compare the frequency in two groups with repeated measures in each group
I have two dichotomous variables determining the cut-off point in the measurements taken before and after the manipulation. Not all observations are independent of each other, as for some subjects ...
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Grouping most strongly contributing items between different samples
I am performing an analysis by using Python's collections.Counter to obtain a scale of frequency x rank. I obtained the same statistics for multiple datasets and ...
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hypergeometric test for gene feature enrichment on population frequency data
I have a data frame that represents the frequency of gene features in the background population, and several sub populations. For each sub-population, I want to do an enrichment analysis in R with ...
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I have numerous sets of values over a time range representing withdrawals per customer. How do I calculate the most representative set from them?
I am new to analysis and I have encountered a problem that I cannot seem to find information to help me. This may be due to not having the knowledge to formulate the question correctly so I will try ...
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Confidence Level for mean comparison among control and treatment group
I collected data where two players interacted with two choices each, where a 2x2 table resulted when representing the game in strategic form. The 4 outcomes are (A, A) ; (A, B) ; (B, A) ; (B, B). My ...
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How to calculate the mean from bin endpoints and frequencies? [duplicate]
Sometimes data extracted from reports do not have individual values, like 4, 23, 43, but grouped together like this:
income level
people in this group
10k to 20k
44
20k to 40k
240
40k to 80k
400
...
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Fisher Information for frequency estimation under non-circular complex Gaussian noise
Consider a non-circular complex Gaussian noise $v$, which is given as $v = v_r + iv_i$. Here, real and imaginary components are independent and are Normal random variables such as $v_r \sim \mathcal{N}...
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Which graph to use for unequal class widths AND huge frequency range
I recently saw a question where they wanted us to plot an appropriate graph for classes of unequal widths, starting from 0. Normally, we'd have used histogram but then the frequencies ranged from 33 ...
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Stationarizing Time-Series
This is a general question about stationary time series.
Consider a time-series t with frequency k (e.g., 52 for weekly data).
If this time series was non-stationary such that a single difference (i.e....
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Relation between Fourier transforms and coherence of signals
My overall aim is to compare the edges of two images by comparing their Fourier Transforms (FFT) and to calculate one number as a key performance indicator that describes how much they are similar to ...
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How to convert high to low frequency data
I have data for a macroeconomic variable, and it has monthly frequency but I need to work with it in quarters. Is there a statistical method to perform this frequency conversion that ensures the least ...
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How to assess if a distribution has significantly changed over time
I'm studying the incidence of different types of influenza in a country over several years. In particular, for years from 2015 to 2020 I know the relative abundance of 3 types of influenza (% of ...
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Test to compare frequencies?
I want to be able to see if an insect has a statistical preference for flower colour, which test should I use as the data is frequencies and I assume using Chi-squared wouldn't work. For example I ...
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significance test to compare race-ethnicity among 4 groups
I am trying to figure out the right significance test to determine which of my 4 groups are most (1) non-hispanic white (2) non-hispanic black (3) hispanic or (4) other compared to other groups. In ...
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Determining if two groups of uneven size have the same distribution?
I have two groups, an experimental of ~100 and a control group ~1000. I want to pick a selection of 100 from the control group at random to be the proper control for the experimental group.
Before I ...
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How best to display skewed frequency data?
I am counting the number of eggs laid each day by some animals. Most days under my experimental conditions, individuals produce 0 eggs (194/307 observations). I do not want to leave these 0 days out ...
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Is there a way to determine if one picture is more random than another
I have two pictures. I only want to keep pictures that "display" randomness. Is there a way to distinguish more random from less? In these plots, time is the vertical axis. So, the second ...
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Frequency of timeseries greater than half the number of datapoints in timeseries
as suggested in the following thread:
Period detection of a generic time series
I'm testing the function findfrequency() to automatize the estimation of the period ...
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Comparing differences in frequencies
Let's say that we have four groups of individuals, namely groups A, B, C and D, randomly sampled from a greater population (in the underlying population, each individual also belongs to one of those ...
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How do I deal with nonexistant data in an irregular frequency time series?
I am trying to do some time series analysis on the margin resulting from three specific commodity futures contracts and ultimately forecast the margin. The margin is calculated as M = F1 + F2 - F3. I ...
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Assessing the fit of a distribution of absolute frequencies to a distribution of relative frequencies
Problem: From a related paper, we have a distribution of relative frequencies for a set of actions people do when working with a particular tool. In a study of our own, we measured a set of absolute ...
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Frequency of mutants in a very large number of observations
During cellular division (generation of two cells from one) bacteria experience mutations, where a newly produced cell harbors altered genetic code. To measure the rate of this happening Max Delbrück ...
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