A brief numerical description of a set of data.

learn more… | top users | synonyms

1
vote
1answer
11 views

Allocating consumption to products

Following scenario: Data from 12 truck companies is available. For each company the absolute value of diesel consumption is available. Each truck company can ship Product A, Product B and Product C – ...
2
votes
1answer
14 views

How to display potential outage when usage fluctuates greatly among customers?

I work for a Health Information Exchange. We have numerous "participants". Some send hundreds of messages a day, some might go a day or two without sending any messages. I'm creating a daily report ...
0
votes
3answers
44 views

How to summarise information in a correlation matrix? [closed]

I have ten variables, which I have correlated against each other. I get a correlation matrix of size $10\times10$, where the correlations are relatively high on average. I would like to somehow sum ...
3
votes
0answers
49 views

Log Transformation

I am planning to run a 2x2x3 repeated measures ANOVA on reaction time data pre and post treatment. However, my data is skewed and I wanted to do a log transformation but have few questions. Can I ...
0
votes
1answer
21 views

Meaning of a higher out-of-sample $R^2$ but also a higher MSPE

I am comparing several forecasting methods using the out-of-sample $R^2$ and MSPE. Now I have encountered situations in which the $R^2$ of a certain method is higher than that of the other, but the ...
3
votes
1answer
73 views

What's the meaning of dimensionality and what is it for this data?

I'm doing my assignment for my "Modeling and Optimization" course, and now I have doubts on the first question: What is the dimensionality of the data? What are the min, median, max, mean, ...
0
votes
0answers
7 views

quantiles over moving window

A subrutine of a computer library calculates the quantiles over fixed spaces for all of my dataset : eg it calculates: ...
0
votes
1answer
25 views

Analysing data from summary table on R (interactions)

If I want to test whether data[,1]:setB is equal to 0 or not, do I just use the given t value and p value or do I need to add it with the data[,1] values? looking at the p value of data[,1]:setB, I ...
1
vote
1answer
34 views

Rewriting RegressionSS

I am having troubles in deriving the RHS of this formula: $$RSS= \hat{\beta}^{T}Z^{T}y-n\bar{y}^{2}$$ where $Z$ is the design matrix I am given ${y}^{T}y$ (what exactly does ${y}^{T}y$ stand for and ...
2
votes
1answer
47 views

How to rank monthly data, using both trends and averages

I have a very large data set containing the daily searches for some Wikipedia entries. I am using the number of searches as proxy of popularity and want to rank the entries. Lets say I have entities ...
1
vote
0answers
33 views

Quantifying how uniformly spread out points are?

I'm looking for a way to quantify how "clumped" vs homogeneously/uniformly distributed points are in a graph. Each collection has 100 points as (x,y) pairs. I've attached two graphs as an example. ...
0
votes
1answer
28 views

De-normalizing Google Trends data?

Does anybody have suggestions on how to de-normalize Google Trends data? The site says that their trends are made with the following metric: The numbers on the graph reflect how many searches ...
0
votes
0answers
11 views

Statistical Comparison of two different waves

I have two waves data for a couple of cities and I need a comparison W I W II City A 10,000 10,100 City B 200 202 City C 1500 1515 There is a 10% increase of ...
0
votes
0answers
21 views

Averaging standard deviations of unequal weight?

I'm sorry if the title is unclear, but I'm not sure of the appropriate way to phrase this question. I'm in med school (and sadly not as versed in statistics as I ought to be), and I am trying to use ...
0
votes
0answers
24 views

Descriptive and Inferential Statistics

I am doing a time series analysis (stock market returns) and I am currently looking at the summary stats. I know the definitions of the individual stats but the one I am stuck on is the relationship ...
3
votes
1answer
85 views

Using a rolling window in time series regression

I am learning about regression. I have done some cross sectional regressions which are fine. I recently did a simple time series regression. So I have a y & x vectors each containing 1000 ...
0
votes
0answers
56 views

Is there a name for this sort of plot? Is there any reason not to use it?

Suppose we have some time series data, with multiple samples per time unit. For example: ...
3
votes
1answer
89 views

How to compute the pdf analytically for the sum of generalized gamma

Question: problem statement $$z^d = \sum_i x_i^d $$ pdf of $X = \frac{d(\lambda x^d)^n}{x \Gamma(n)} \exp(-\lambda x^d)$ which is a generalized Gamma distribution and they represent euclidean ...
0
votes
3answers
62 views

interpret scatter plot if there is anything to interpret from it

I have an x variable and a y variables. I have done a simple scatter plot. I however don't really know how to interpret (if there is anything to interpret) the plot. I can't find any other similar ...
1
vote
0answers
34 views

MECE statistics

Consider a sample of a real quantity $X$. Say that we divide this sample into two mutually exclusive and collectively exhaustive (MECE) groups. Say we know the mean and median of these two groups, ...
0
votes
1answer
62 views

A Simple Regression Model for Our Experiment? [closed]

We know, In statistics, simple linear regression is the least squares estimator of a linear regression model with a single explanatory variable. In other words, simple linear regression fits a ...
0
votes
0answers
19 views

How to show ancillary statisitc of normal random sample?

Let $X_i \sim N(\mu,\sigma^2)$ and $X_i$ are independent. Then how to show that: $$ T = \left(\frac{X_1-\bar{X}}{S},\frac{X_2-\bar{X}}{S},\ldots,\frac{X_n-\bar{X}}{S}\right) $$ $T$ is an ancillary ...
1
vote
1answer
25 views

Suggestion on algorithm to visualize the safeness of an area [closed]

I am actually developing an app that notify users about "Safety Index" of the surrounding in a range of 1 Kilometer radius. I have did some research on how to calculating crime index which uses the ...
5
votes
0answers
153 views

A tricky question about correlation [duplicate]

$X$, $Y$ and $Z$ are three random variables where their pairwise correlations are the same, i.e., $corr(X,Y)=corr(Y,Z)=corr(X,Z)=\rho$ what are the possible values of $\rho$? I was asked this in an ...
0
votes
2answers
29 views

Would this situation be a ratio of 1/5 or 1/10?

Hypothetical situation that I'm trying to use for understanding some criminal statistics. Let's say there is a city with 10 banks. One criminal robs two banks before being arrested and placed in ...
1
vote
1answer
83 views

assumptions made for a normal distribution- a interview question

I was asked in my interview: What assumptions can you make? Why and when? (i.e When is it safe to assume "normal"). Can some one answer this .
9
votes
1answer
128 views

When would we use tantiles and the medial, rather than quantiles and the median?

I can't find definitions for either tantile or medial on Wikipedia or Wolfram Mathworld, but the following explanation is given in Bílková, D. and Mala, I. (2012), "Application of the L-moment method ...
2
votes
1answer
37 views

Is this a valid use of “positive predictive value”?

So here's your typical table for evaluating the performance of a diagnostic test: Gold standard result ...
0
votes
0answers
17 views

What effect do outliers have on standard deviation and the IQR?

I understand that they will both sorta increase, but if i remove them how will the bulk of my data change? for example in a boxplot/ histogram
1
vote
0answers
20 views

How to find the probalities of a,b,c (mutually exclusive events) when i turn the problem into three binary classification problems?

I am using scikits linear logisitc regression to classify three events a,b and c. it works better (score) when i convert them into a binary classification model. such as: 1. M1 classifies a or b 2. ...
4
votes
0answers
116 views

Caclulating standard errors for generalized least squares without raw data (just sample means and covariance)

I have a question very similar to the question asked here: is it possible to calculate standard errors (specifically, the standard error of the intercept) for generalized least squares regression ...
6
votes
3answers
258 views

Will two distributions with identical 5-number summaries always have the same shape?

I know that if I can have two distributions with the same mean and variance be different shapes, because I can have a N(x,s) and a U(x,s) But what about if their min, Q1, median, Q3, and max are ...
1
vote
0answers
6 views

Analysis of possibly correlated small sample data

I'm doing an experiment where I'm imaging 3 groups of 5 rabbits (total = 15 rabbits) using 4 different machines at 4 different anatomical locations to see if a radio-opaque material is visible in all ...
4
votes
1answer
104 views

Estimate mean & standard deviation of set S if I know stats of an inner set and outer set

Suppose I have sets $S_1\subset S_2\subset S_3$. I know exactly the size, mean, and standard deviation of both $S_1$ and $S_3$ and want to estimate the mean and standard deviation of $S_2$, where I ...
6
votes
2answers
168 views

Standard error of regression coefficient without raw data

After searching here: Perform simple regression without raw data I am still curious about this. Is it possible to derive the standard error of a regression coefficient from summary data alone? ...
0
votes
1answer
20 views

Using stat methods on summary statistics

Is it ok to use statistical methods on summary statistics, as they're random variables? I ran into an interesting problem while working with a client, but will try to keep it very general as the ...
0
votes
1answer
83 views

Log form of variables and descriptive measures

Because of larger values of variables, I did a log- transformation in my dataset. Now I want to give a descriptive table regarding my variables like mean, max, min, median, skewness, kurtosis. Can I ...
0
votes
0answers
36 views

What are the quantitative methods alternative to Meta-Analysis?

What are the alternative statistical quantitative synthesis methods for combining studies, if we can't apply meta-analysis because of the heteronegeity or the shape of the data, for the data set of ...
0
votes
0answers
56 views

Which method should I use to combine the data of my studies?

I want to make a meta-analysis on household consumption expenditures elasticity data. In these studies that I've got; methods and regions and etc. varies according to studies. But at last, the results ...
0
votes
0answers
54 views

What summary statistics can be applied to the results from a multiple choice question?

I have a list of answers given for a multiple choice question. For multiple choice I mean that from a set of possible answers given, more than one can be chosen. For other answers with single choice I ...
3
votes
0answers
356 views

Partial correlation and multiple regression controlling for categorical variables

I am looking through the linear association between variable $X$ and $Y$ with some controlling variables $\mathbf{Z} =(Z_1, Z_2, Z_3, \dots)$ One approach is to do a regression $E(Y)= \alpha_0 ...
1
vote
0answers
27 views

Calculating overall variability over multiple datasets

I am trying to determine a way to measure the consistency of transit hours performed by transportation providers over their entire portfolio of shipping routes. For example, if a company has 3 ...
4
votes
1answer
40 views

How to represent data graphically in which a respondents can choose more than one group?

I am analyzing a survey in which one of the questions was (What is the industry segment of your company?) and the respondents can choose more than one category. I have used a pie chart to represent ...
1
vote
0answers
37 views

How did they do this analysis? (weighted proportions)

I've read with interest the report by Ayanian et al "Racial and Ethnic Disparities among Enrollees in Medicare Advantage Plans" [1]. They have estimated adjusted proportions of individuals that ...
3
votes
3answers
714 views

glm in R - which pvalue represents the goodness of fit of entire model?

I am running glms in R (generalised linear models). I thought I knew pvalues - until I saw that calling up a summary for a glm does not give you an overriding pvalue representative of the model as a ...
0
votes
0answers
26 views

How to implement Exponential Histograms

I am having trouble in understanding the concept of exponential histograms. They are known to be much efficient for maintaining statistics. I have read it in this article but cant understand how they ...
2
votes
0answers
13 views

Quantitative tail sizing

What is the most generic way of deciding whether the tail of a dataset is long or short? In other words, what would be the unit-free summary metric m that could be ...
3
votes
1answer
34 views

How to prove that the permutation of the points are the minimal sufficient statistics for Cauchy distribution?

I see this everywhere that the permutation of the samples $X_{(1)}, ..., X_{(n)}$ is the minimal sufficient statistic for the Cauchy distribution [1]. It is clear that it is a sufficient statistic,but ...
-1
votes
1answer
62 views

Appropriate statistical analysis to use

I have built and tested a computer application, which involved two participant groups (Group-A with existing knowledge of databases and Group-B without knowledge of databases). I was required to apply ...