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

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Estimating the distribution of frequencies from a sampling of unique values

Let $L$ be a list of elements with repetitions, and $S$ be the set of elements appearing in $L$. I have two tools at my disposal: I have a sample of $k$ elements taken uniformly in $S$, and for each ...
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261 views

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 ...
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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 ...
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30 views

Why 'Assumption of Uniformity' for Mean?

I am teaching some very basic statistics for grouped data. In a different class a few years ago I made an 'assumption of uniformity' about the data: within bins, data is uniformly distributed ...
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How to count these transitions - in R [migrated]

Given a table of values, where A = state of system, B = length of state, and C = cumulative length of states: ...
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43 views

How to calculate a mean of a sample where some measurements do not match a normal distribution?

I have a set of temperature measurements from amateur meteo stations around the place I live in. Being amateur meteo stations, the measurements vary because of the placement of the probe, measurement ...
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Generate samples from frequency table with fixed values [migrated]

I have a population 2x2 frequency table, with specific values: 20, 37, 37, 20. I need to generate N number of samples from this population (for simulation purposes). How can I do it in R?
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20 views

Can a value appearing more frequently for a class help predict it?

I am trying to analyse my data before doing multi-class classification with SVM. I have several variables. I pick one of them and study it. This is a categorical variable. It can have the value 0 or ...
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7 views

Frequency of phenotype based on probability of genotypes

I know that in genetics you never know the frequency of any trait, even if you know the probability of having that trait. For example I know that the probability of having A+ blood is = P(AA+/+) + ...
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6 views

how to estimate the loading factor for a travel company?

I am pretty naive to statistics, so please correct me where I am wrong. I am trying to estimate average case loading factor for travel company. This travel company is running shuttle service wherein ...
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1answer
50 views

Hypothesis testing: test difference in frequencies

I have sampled some data, and want to argue that one class of events is more common that another class of events. To get concrete, let's use an example involving text. Suppose I sample some English ...
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29 views

Analysis method for nominal dichotomous data from mixed design

I have the following data set (example): Subject Treatment-group Decision_x Decision_y Decision_z 1 1 A B A 2 1 B B ...
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1answer
63 views

Testing for top 3 options

I have data as shown in the chart below. There are 1144 rows of data and for each data row, an event (A, B, C, ..., I) could either have occurred or not occurred (that is, on or off; binary). For ...
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Expected frequency (per million words)

I'm trying to figure out what this paragraph means: The final measure was (like #2 and #3) designed to exclude discipline-specific and technical words. It states that the word cannot occur ...
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1answer
37 views

Calculating expected number of zero-crossings of a white noise process

I am curious about how to calculate the expected number of zero-crossings of a white noise process over some time $t$. In particular I would like to be able to deduce the expected frequency of ...
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1answer
43 views

Difference between samples in terms of frequency ranks

I have 3 different texts, and for each one of them, I have the frequencies of 25 letters appearing in those texts (Text A, letter A, freq = 5013; Text A, letter B, freq = 1462,...). These texts have ...
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23 views

Finding a representative upper limit of a large dataset

I have summer cumulative solar radiation data derived from a model on an area in North-West Italy. I extracted the modelled values from specific regions (i.e. within rock glaciers outlines), obtaining ...
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37 views

Cramer's V and word frequency

I am investigating the frequency of a word in two distinct corpora. In one corpus, it occurs 232 out of 189,489 times, and in the other corpus it occurs 4394 times out of 559,715 times. The result of ...
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47 views

Log vs. double normalizing of Term Frequency

In the wiki page on Term Frequency-Inverse Document Frequency (tf-idf) there are two interesting TF weights: Double normalization $K$: $K + (1-K)\frac{f_{t,d}}{\max_t f_{t,d}}$. In this question I ...
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Inference of frequency of values in a poisson distributed histogram

For some data there is a histogram, which has bins with varying sizes. Is it possible to infer the frequency of the values for smaller segments of the bins, favourably with Matlab? With the attached ...
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31 views

Poisson distribution vs Three-way table to Compare multiple incidences

I need some help understanding the difference between comparing incidences of rare events with a Poisson distribution and using a three-way contingency table. I'm sure I have some fundamental ...
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86 views

The frequency in histograms

My question is trivial, but the problem is that I found contradictory answers on internet. So I have the following sample data: ...
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33 views

Normalization of distributions

I am measuring intensities of structures in biological tissues, which gives a series of values for each sample. There is high variability between values for each samples from unknown procedural ...
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40 views

Assigning weights (or importance) based on frequency

Data I have prepared the data (67 dimensions) in the form of vectors like: 1,0,0,0....66 times 0 (just 1st dimension having ...
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7 views

Statistic way to find a threshold for NGrams occurrence

I got a vector of Bi-Grams with their occurrences, and I have to calculate tri-grams from the most occurrent bi-grams. Therefore I need to find a statistic way to find a threshold of big-grams ...
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Analyzing changes in the structure of (a) population(s) across time

I´d like to know how to compare populations of test takers taking an exam, in order to know whether there are significant changes in the structure of the group of test takers across several years. I ...
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1answer
63 views

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 ...
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Am I breaking the assumptions of the Poisson distribution?

The Poisson distribution arises when events are counted within a specified interval. I've recorded the number of events each month (I'll not discuss what these events represent). This appears to meet ...
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97 views

Find the values between percentiles in a frequency distribution

In the distribution below, how would I find the values that lies between 30% and 50% of the distribution? R code would be handy but not essential! 28, 28, 29, 30, 30, 31, 31, 31, 31, 32, 32, 32, 34, ...
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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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1answer
31 views

How to perform a filtering to get the low, middle and high frequency components of an image?

I am currently looking into some image processing project and just wondering how to obtain the low, middle and high frequency components of an image? For example, as this picture showed (I got it ...
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29 views

What are the criteria to choose for a bootstrapping, frequency, forecasting of fitting method to fit demand data?

My goal is to calculate the inventory height of several products. To do so, I have to calculate the probabillity a certain demand occurres. However to determine the distribution based on historical ...
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37 views

Cumulative distribution percentage in Lorenz curve

I have dental caries data based on two different indices. I have already calculated the logistic regression using binomial outcome for each of these indices. However we found that a portion of our ...
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1answer
114 views

Researching the frequency stability property

I have seen this short, wonderful video about the frequency stability property (also there is another video from this guy under his Kickstarter project ArtOfTheProblem; they are both great, and I ...
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Comparing frequencies

I'm trying to find the right test to use to compare 3 frequencies. Basically, in my research, 3 separate user interface prototypes were given to the same sample (10 people) and particular tasks needed ...
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Differing frequencies for time series ts() function in R

I understand the frequency argument of the ts function in R is set to work for monthly, quarterly, yearly data, etc. In my case, ...
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31 views

Quantifying 1 factor count data with variable # of categories

I feel like this should be an easy question, but after lots of looking I"m stumped. I deal with continuous data almost exclusively, but in my infinite wisdom I designed this study that yielded ...
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48 views

Term importance from document with predefined weight

I am having a set of document with different value weight on them. I am trying to understand which term from the documents trigger the highest values. I have a theory on how to do it and I would like ...
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1answer
67 views

Which test? Chi-square, non-parametric or Poisson Regression..? What species is the most frequently observed

I'm reposting my question based on previous comments received. The problem: 10 x 100m sections of shoreline have been sampled to determine if one species is the most frequently observed species ...
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51 views

Is the frequency of one observation greater than the frequency of others

Suppose I have 10 bags of M&M's. I count the number of red, blue, green and brown M&M's in each bag. I want to know if there are more red M&M's than other M&M's in the bags and if this ...
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36 views

Frequency change monthly series

I have a monthly series and I want to make it quarterly. I want to know which method I use. I used an arithmetic average but I do not trust these results. There is a procedure in Stata and Eviews I ...
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Differences in variables constructed by counting.

I have constructed a frequency variable from counting events of certain magnitude (e.g, 1,2,3...) from a time dependent experiment with animals. I have two groups (Trained vs Control) and two phases ...
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32 views

Frequency analysis from time dependent data in R

I've got a time dependent data from animal recording. My data has two groups (TR and UT) each group has 20 replicate. Tiempo (time) variable goes from 282 sec to 318 sec. I have a turning point at 300 ...
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403 views

Calculating Mean and Standard Deviation From Frequency Chart

I have only a frequency table like that below. How can I get the mean and standard deviation? ...
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63 views

How to get corpus used for word-frequencies for languages other than english?

I have taken a corpus of English for finding the word frequency in giving recommendation for spelling mistakes. I just used simple : Edit Distance between ...
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39 views

Best statistical analysis method for frequency data

I'm designing a between subjects experiment with 1 dependent variable with 2 levels (manipulation & Control) and 4 dependent variables which are all categorical (Yes/No). I would like to see the ...
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60 views

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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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 ...
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97 views

What do you think is the right tooling to separate sub-time series from a single big time series?

I would like to separate a big time series into its components to improve forecasting. To clarify: I would like to find the different components - maybe it is better to say frequencies which ...
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136 views

Comparison of frequency rates

Patients with chronic schizophrenia will take some antipsychotic drug during some period of time. The frequency of schizophrenia for each patient will be recorded before and after that period. I ...