Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [frequency]

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

The frequency measures the number of times an event occurs in a data set. The absolute frequency counts how often each event occurred in the sample whereas the relative frequency divides the absolute frequencies by the total number of events. This gives the relative probabilities of the occurrence of a particular event.

Frequencies are often plotted by histograms or kernel density estimates. When plotting absolute and relative frequencies with the histogram the shape of the distribution does not change. Only the values on the x-axis change.

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Period detection of a generic time series

This post is the continuation of another post related to a generic method for outlier detection in time series. Basically, at this point I'm interested in a robust way to discover the periodicity/seasonality of a generic time series affected by a…
gianluca
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Mean absolute deviation vs. standard deviation

In the text book "New Comprehensive Mathematics for O Level" by Greer (1983), I see averaged deviation calculated like this: Sum up absolute differences between single values and the mean. Then get its average. Througout the chapter the term mean…
itsols
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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, and I think this is a valid answer. However, my…
Maximal Ideal
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How to measure the statistical "distance" between two frequency distributions?

I am undertaking a data analysis project which involves investigating website usage times over the course of the year. What I would like to do is compare how "consistent" the usage patterns are, say, how close they are to a pattern which involves…
user258128
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How to figure out what numbers often appear together in a dataset?

I have a lottery style dataset we produce internally (example below). I am trying to figure out which numbers appear most frequently together. Example questions: What are the top 10 pair of numbers that appear most frequently together? What are the…
daniellopez46
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Why does multiplication in the frequency domain equal convolution in the time domain?

This question came in the context of understanding how to get a distribution of a sum of two iid random variables. I'm working through the top answer to this question Consider the sum of $n$ uniform distributions on $[0,1]$, or $Z_n$. Why does the…
Anton
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Frequency jump detection

It is generally known that 'jumps' in frequency data are difficult to estimate. In the current literature, many different techniques for estimating such jumps have been tested and often with satisfactory results. A summarizing paper about some of…
Jean-Paul
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Visualization of binned frequency distribution in R

I am trying to visually represent the distribution of last names in the US. Specifically, I am trying to show that the distribution is such that the most common names (say the top 50) are very common but that it drops off quickly after that. The…
Sam Swift
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What's a good approach to estimate the probability of word frequencies?

I have a document corpus and I want to estimate the probability of occurrence of a certain word $w$. Simply calculating the frequencies and use such a number as an estimation is not a good choice. Is there any work on this topic describing a better…
derekhh
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How do I quantify the uniformity of sampling time?

My datasets cover a long time, say 20 years, and the data are sampled at different time. For example, some are obtaiend at 1:00(stored as 100), some are 23:00(2300). If I plot the histogram of the sampling time, it will look like this: And some…
cqcn1991
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chi-squared to test if two variables have the same frequency distribution

I want to test if x and y have the same frequency distributions using chi-squared. In my code below, I've concluded that because the P-value of the chi-squared is >0.05, then I found no evidence that x and y have different frequency distributions.…
luciano
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Statistical comparison of two signals

I need to develop an algorithm that will compare two signals and generate some metric(s) to describe changes between them. Signal processing and analysis isn’t my strong point so I would appreciate any help! Here is an example of what the signals…
user41991
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Most significantly frequent category

I am measuring the frequency of consonants in a sample lexicon of a language. The results are as follows: +-----+-----+-----+-----+----+----+-------+ | p | t | k | m | n | r | Total | +-----+-----+-----+-----+----+----+-------+ | 278 | 256…
lotomat
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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 something like this. I have to measure the period…
jinawee
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Does Sampling Frequency matter for Time Series analysis?

I am given two time series of prices between 2009 and 2013. Price series A is weekly data, series B is monthly data. I would like to compare some basic descriptive statistics of these two time series data (such as mean, standard deviation…
MM Cui
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