# Questions tagged [frequency]

The frequency measures the number of times an event occurs in a data set.

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### How to measure the period of an oscillation with least error?

I have a question about analyzing the data from a coupled pendulum. I have measured the amplitude $\psi(t)$ which is expected to be a beat and I want to measure the period. The ideal plot would be ...
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### Statistics question related to the Charleston shooting

Note: This will be a long post, and I apologize for that. There's been a lot of parsing of President Obama's words with regards to the "frequency" of shootings in other countries. I contend he's ...
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### Granger causality tests when series are measured at different frequencies

As a research exercise I should perform Granger causality tests on pairs of national series (one describing output gap and the other an index of consumers' confidence). However, I face a situation ...
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Assume there are (always) $N$ bottles of milk on the grocery shelf. Each day, a deliveryman randomly selects a fixed $M \lt N$ bottles of milk from the shelf and replaces them with new bottles of milk....
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### How do I compare frequency data of more than two groups?

I am comparing the frequencies of a disease presenting in particular season. The expected proportion would be 0.25 and the observed frequencies for spring, summer, autumn, and winter were 7, 9, 11, ...
165 views

### How to determine significant differences between frequency spectra?

I want to determine whether the mean of frequency spectra are statistically different from each other. I have a set of trials in different drug conditions and I want to test whether a drug had an ...
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### Discrete Fourier Transform and uneven sampling

In this blog article an example is given of one can use the DFT to detect frequencies much higher than the sample rate. In the comments sections I asked how it was done, since DFT normally requires ...
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### How to set the optimal value to a trigger signal?

I have an indicator which oscillates between -50 and +50 values. Then I have to set a optimal signal value to go long or short. I've thought in something like this: ...
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### Modified German Tank problem involving string distance metrics

Pretend we have a list of items, e.g. names, and we know it is sorted ALPHANUMERICALLY let's say in ascending order. Given a small set of the first K items, how can we estimate the length of the full ...
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### How to deal with frequencies that don't appear in the held-out set?

The held out probability is defined as $$P_{HO}\left(x\right)=\frac{t_{r}}{N_{r}\cdot\left|S^{H}\right|}$$ where: $t_{r}$ is the total number of times events that appeared $r$ times in the training ...
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### Suggested algorithms for time series analysis of sporadic events

I have a series of sporadic, discrete time series events that appear to occur in shorter interval clusters and I am looking for a way to determine the frequencies at which the events occur. None of ...
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### Chi-square on a categorical variables (derived from continuous distribution)

We know that Chi-Square can be used with categorical data (such as Male/Female, Republican/Democrat, etc). However, I convert my original continuous data to ...
399 views

### Frequency with repeated measures

I did an experiment in which I group objects based on machine learning. I then tested whether people group them in the same way. Each subject (I had 30 subjects) watches 8 sets of 3 objects. In each ...
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### Is there a better term for frequency distribution of a term frequency?

I am wondering if there is a better way of formulating this and also if this is a correct way of formulating it. What I'm trying to represent in the frequency distribution is the count of documents ...
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### Generalization of skewness detection in non-uniform case

I am not sure if my title reflects what I am attempting to ask. Let me elaborate my question. I want to classify an observation/feature into one of two categories ($A$ and $B$) based on frequency of ...
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### Is Rule of Three inappropriate in some cases?

I'm building binomial proportion confidence intervals for a patient dataset containing the frequency of home nursing visits during the week prior to hospital admission. The freq. of home visit ...
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### On the uniform convergence of relative frequencies of events to their probabilities

I have read the article by Vapnik, Chervonenkis "On the uniform convergence of relative frequencies of events to their probabilities" Theory of Probability and Its Applications, vol XVI, n. , 1971. ...
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### Comparing frequencies in two groups between two time periods

I've got data that are essentially set up in two 2x2 frequency tables. I have frequencies that males and females disperse or recruit to a given region. I am interested if the proportion of sexes that ...
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### Specification on power spectral density for population data

What is the best way to put a specification on the single-side auto-power spectral density (PSD)? We have a product for which we have a time signal. For this signal we calculate the PSD (or ...
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### Cepstrum: quefrency scale to frequency scale

Can someone please explain to me how to convert a quefrency scale to the corresponding freqncy? For example consider this: A voice signal is measured at 50kHz sampling frequency and FFT power ...
34 views

### Statistical analysis for quasi-experiments

This is my first message on this forum. I hope I am not doing any mistake. I must analyze data obtained after a quasi-experiment and I am not sure how to proceed. The experiment has been carried out ...
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### Should I use weekly or daily returns for modelling FX returns?

I am currently modelling Foreingn Exchange returns using a GARCH model. I am simulating returns 1-year forward. Would it be better to use weekly or daily data on Foreign Exchange returns? Weekly data ...
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### Fisher's exact test with opposite direction of categories for two groups

I would like to analyze student performance under two teaching approaches for two classes. We predict that class 1 would outperform class 2 and ideally the performance between two classes should be ...
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### How to analyze the frequency of correct/ non-correct answers

I have a question about how to analyze some data. It involves the performance of two equally sized groups in a questionary with 30 arithmetic questions that I scored with two possible outcomes (...
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### calculating sample size needed for a target confidence interval from categorical data

So I will have data sorted into one of five bins (flow cytometry sorting of cells). These bins are actually adjacent categories that quantify a single fluorscence level (0-20,20-40,40-60,60-80,80-100)....
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### Relative frequency question

I am a new user here, and I need some help getting started with the following question: The textbook answers are a. $19$ and b. $20$. How do I begin this question? I am a beginner in statistics. :) ...
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### How to analyze size frequency data from over 70 sites

When I started my PhD, I had virtually no prep-time. My advisor needed me in the field and told me to go grab samples. As such, my planning wasn't the best, so sorry if this is a completely terrible ...
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### Estimating standard deviation from cumulative frequency table

I've been provided with some data in the form of a cumulative frequency table, where each value is exceeded a qiven percentage of the time, so for 99% of the time the readings exceed 163 and for 1% of ...
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### test significance for frequencies

I have frequency data for six datasets (3 control samples and 3 treated samples) consisting of values for physical stiffness, when I plot the frequencies against stiffness it looks like the treated ...