# Tagged Questions

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### How many eligible bachelors in a city? [closed]

This is a very simple question posed to me by a friend of mine. I know it's a statistical analysis problem, but I suck at math. Given the total population of $x$ within a metropolitan area, what ...
34 views

### Similarity measurement for strings of letters

Let's say, I have 10 different groups, and each group has its own string sequence. So, it should be like : G1 -> CHFAIEBD G2 -> HCFJIGBD G3 -> HCFAIJBD G4 -> HFCIJEBD G5 -> ..... G6 -> .... The ...
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### Creating a polynomial function with no x-intercept

I have an understanding of polynomials and how to create a function based on the leading coefficient, degrees, x-intercepts, etc. My question is how do i go about creating a polynomial function that ...
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### Finding similarity between elements using statistics

I have a dataset of DJs in which I'm trying to find DJs similar to a specific DJ. Each DJ has a set of a genres with a certain percentage. How can I find the similarity between 2 DJs? The following is ...
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### Median value resulting in negative number

I know the that the formula for finding the median of grouped data that is: $$\mathrm{Median} = L_m + \left [ \frac { \frac{n}{2} - F_{m-1} }{f_m} \right ] \times c$$ And I also know what the ...
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### Data interpretation problem

Approximately what is the minimum amount of caffeine, in milligrams, consumed per day by a person who daily drinks two 10-ounce mugs of percolated coffee and one 12-ounce cup of a caffeinated ...
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### Estimation of real estate

I'm working on a project on estimating the price value of real estate. First I have collected a lot of data (500 000 instances) with details such as postal code, number of bedrooms, build year, ...
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### Work out if the relationship between 2 datasets is constant

I have 2 one-dimensional datasets, let's call them a and b. I want to know the correlation between ...
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### Is there a way to use the Generalized Mean to find the “best” possible mean to use for a specific data set?

I've recently learned about the Generalized Mean as an abstraction of the many different means, includeing the Geometric, Arithmetic, and Harmonic means, as well as others. It is my understanding ...
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### Survival analysis in survey dropouts?

I am working with a survey data set and am curious about who abandoned it before finishing all the questions. I have information on how many questions each respondent answered (no skipping allowed) ...
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### Finding the range from standard deviation and Gaussian Curve

The figure above shows a normal distribution with mean m and standard deviation d, including approximate percents of the distribution corresponding to the six regions shown. Suppose the heights of a ...
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### Calculating Inflection Point in Real World Data

I can think of a few ways to get a good grasp of this problem from an experimental perspective, but I'm looking for a more general explanation that can be applied to different situations. If this ...
18 views

### How to evaluate the difference between two classes of data which are highly overlapped

I’m trying to implement a classifier based on a dataset comprising two classes of high dimensional time-series observations (the values of the two classes of observations are highly similar). I ...
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### What method should I use for this optimization / feature selection project

I'm going to describe a problem and I'm not sure how to best solve it. I will describe the situation. When answering please recommend a method and maybe a software library. I'm using Python for my ...
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### Data normalization methods for RNA-seq

Not sure if this is the best place to ask such a question, please re-direct me if there is a more appropriate site. I am using bioinformatics software to look at gene expression levels in populations ...
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### Bivariate Correlation Unique solution

I have a set of data, let's say "score vs loss ratio", the score is an arbitrary number I gave to a team by looking at their past history. I want to prove my hypothesis which is higher the score, high ...
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### Variance of Estimated Coefficients in Logistic Regression

I have a logistic regression model with a binary variable as the response and a categorical variable with 3 categories as a predictor. The fitted model is: logit(P(Y=1)) = intercept -0.19*C2 + ...
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### Addition of two box plots

I have two box plots that I'd like to add together to form one box plot representing both plots in one. Here's an example of two box plots: At a school 200 boys and 200 girls participated in a test. ...
31 views

### Find spikes in data

I have some datasets and I need to find spikes in them. Imagine the data looks like trading data. If the spike is big enough, I need to log it, otherwise, proceed in the analysis. I tried with a ...
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### Is Expectation Propagation (EP) affected by the prior?

I understand EP by reading Minka's thesis: http://research.microsoft.com/en-us/um/people/minka/papers/ep/minka-ep-uai.pdf I'm trying to apply it to solve a Bayesian inference problem. However, I'm ...
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### Maths concept for salient point in graph data

I have collected data concerning the total post counts of users in an online forum (see graphic). What I am hoping to do is compare the language of 'first posts' with the language of 'later posts'. ...
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### How to compute a “weather” score for repeated trials over time, with a bias for recency

I'm doing some analysis on repeated software tests that can either pass or fail. For each test, I've collected a set of historical (pass/fail, timestamp) records, and I'd like to compute a score to ...
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### How to appropriately normalize financial data?

I am evaluating a normalization of financial data. Two colleagues feel certain of a certain approach, and I am befuddled. The approach shapes the results how they want (i.e., brings possibly extreme ...
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### Fit Conditional Probability Given Continuous Response

Given a sample of data, all the techniques aimed to find conditional probabilities of the response variable require that this is dichotomous or at least categorical (see multinomial logistic ...
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### Analyzing data to determine seasonal indices?

The quarterly sales levels for the past four years of a leading tyre manufacturer are displayed on the table table How to analyze the data to determine the specific seasonal indices,and what ...
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### 2D data fitting

I have some numbers as a function of 2 variables: $(x, y) \mapsto z$. I would like to know which function $z=z(x,y)$ best fits my data. Unfortunately, I don't have any hint, I mean, there's no ...
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### Is there a scientific way to assign weights to historical data?

This is a common question I usually face while processing historical data. I have year on year data of an event for the past N years.I would like to assign weights to the data of these N years so that ...
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### Decision to market one or the other game, based on the expected demand

For example, there is a new video game to market, lets call it Game 1, and there is a 0.60 probability that its competitor will produce a new game similar to it. (This 0.60 may not need to be known ...
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### Fitting discrete distribution (negative binomial) for early data values

I'm having some difficulties with fitting a discrete distribution function (I'm specifically using the negative binomial distribution). Here's my setting: I have a source of incoming items, each with ...
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### Scaling data into $[-1,1]$

I have a data in the matrix for: \begin{bmatrix} 1 & 2 & 3 & 9 & 6\\ 8 & 2 & 7 & 4 & 6 \\ 1 & 2 & 8 & 7 & 4 \end{bmatrix} Each row corresponds ...
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### Best way to generalize a distribution of data into smaller subsets?

Suppose I had a data set as follows: 168.95, 176.83, 178.13, 179.61, 179.44, 172.83, 173.37, 174.06, 174.94, 175.43, 175.73, 175.5, 173.78, 174.06, 172.71, 174.3, 178.38, 178.43, 177.18, 175.34, ...
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### The number of nuts in a package of “Premium Cashews” is normally distributed with a mean of 433 and a standard deviation of 6 nuts.

The number of nuts in a package of "Premium Cashews" is normally distributed with a mean of 433 and a standard deviation of 6 nuts. Packages with fewer than 420 nuts or more than 445 nuts will be ...
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### Continuity correction: Change P(2 ≤ x < 9) to continuous?

Convert discrete probability into continuous probability using continuous correction: attempt: Discrete: P(2 ≤ x < 9) therefore continuous should be Continuous: P(1.5 < X < 8.5) Is this ...
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### Computing a threshold value for paired data

I have a dataset of vector pairs; for each pair ($x_1$, $x_2$) I have two values $V$($x_1$,$x_2$) and $U$($x_1$,$x_2$) (two metrics). I also know a threshold value $U^*$ such that any pair ($x,y$) ...
191 views

### How do I 'reverse engineer' the standard deviation?

My problem is fairly concrete and direct. My company loves to do major business decisions based on many reports available on the media. These reports relates how our products are fairing in ...
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### How do I calculate the function of an (expected) logarithmic distribution, if I know the area under the curve & one data point?

I'm trying to get the function that lets me determine the value of y, where x is an arbitrary number. In this case, I'm looking at sales charts, and I'm making the assumption that the function is ...
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### Likelihood function of truncated data

I am having a little trouble understanding the concept and derivation of the likelihood of truncated data. For example, if I want to find the likelihood function based on a sample from a ...
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### Significance Tests & Confidence Intervals for Non-normal data

I have 2 nonnormally distributed samples of different sizes (N1~=N2). To evaluate whether there is a significant difference between these samples, I used the Mann_whitney U test (ranksum in MATLAB) ...
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### Non-close-form Regression Research

As I try to process some physic experiment data that I don't have the closed form formula with unknown parameters, I have to use some regression models like polynomials or normal distributions . The ...
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### Hypothesis Testing, simple against composite.

i've got some trouble understanding this exercise from Amemiya's Introduction to statistics: Given the density $f(x) = \frac{1}{\theta}$ from $0 < x < \theta$, and 0 elsewhere, we are to test ...
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### Comparing annualised volatility from monthly and annual data

I fear there is a very simple answer to this question and its killing me that I can't see it. I am interested in calculating historical volatility: I have monthly index values starting in Jan 2005 ...
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### Isolating clusters in data

This is a problem that I keep encountering in one form or another every so often. Given a large N dimension space with a sufficiently large (M) sample of points. [1] If I were to be asked to find a ...
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### Mathematical model building with dependent and independent variables

I have been working with data and building models on data. I have developed models in regression using cubic and power series. It works fine for variables with one dependent and one independent ...
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### Experimental Data Analysis

Suppose I have performed 2 different experiments to measure the number of cell in a mice. In the first experiment, we measure the cell in odd day (day 5,7,9,11,13) and in the second, we measure the ...
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### mutual information for power low distributed data?

I have a dataset with power-low distribution, I would like to measure some kind of correlation/mutual information between the data to its class,(for feature selection task), Can I use ...
261 views

### Can you compare data sets with percentages with the Chi Square test?

I’m confused about the Chi Square test.. Apparently you have to use it when comparing frequencies only, but what if both data sets are percentages? e.g. comparing the percentage of smokers in specific ...
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### data interpretation

let us consider following picture and question: INCOME: 1. Money from fund raising programmes, 2. Grant from the government, 3. Contributions from individuals, 4. Contributions from corporations, ...
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### The correct probability distribution / way to analyze daily changes

I am working on a report which is being sent through to end users that should flag to them any "large changes" in the day-to-day values for the past 30 days for something we would assume the ...