Descriptive statistics summarize features of a sample, such as mean and standard deviations, median and quartiles, the maximum and minimum. With multiple variables, may include correlations and crosstabs. Can include visual displays - boxplots, histograms, scatterplots and so on.

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17 views

Use PCA for pattern recognition

I have always used PCA as a preprocessing techniques. There are some people that use it for pattern recognition. Once I used pca to project my data in a 2 dimensional space and then I observed that ...
-1
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0answers
20 views

Statistical technique for two variables

What statistical technique is best to analyse two variables, one being type of downloader (illegal, legal and mixed) and the other is number of devices (which can be 1-7)? To see whether there is a ...
0
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1answer
27 views

How to compute Prior Variance

This might sound a little silly to ask, but I couldn't figure out how an author arrived to the prior variance estimates from this vector: ...
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0answers
8 views

Looking at what content by type of downloader

What statistical analysis test do I need to run? I want to compare type of downloader (Legal and Illegal) to what type of content they download (Music, Movies etc). In SPSS I have set the type of ...
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1answer
63 views

Strength of association test with binary variables

I have a dataset with different purchases for two different items from the same users. So the users purchased the two items at different points in time. I also have 3 different variables: ...
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0answers
8 views

How do you do a power calculation for a 2-phase prevalence survey?

I'm trying to work out what sample size I need to calculate a prevalence rate within certain confidence intervals, using a two-phase design. There is a screener test. Everyone that screens positive ...
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0answers
12 views

Relation between median follow-up and median survival?

When follow-up is assumed to be constant and variable, is there any relationship between median follow-up and median survival? I.e. should one be less or greater than the other?
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0answers
24 views

Determine the significance of factor variables

I have a df like this: ...
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0answers
19 views

Can composite scores of Likert scale be obtained? [duplicate]

I am using a Likert scale for a group of 3 questions. Strongly Agree Agree Undecided Disagree Strongly Disagree I have 3 questions with these possible responses under the category "Effectiveness". ...
1
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0answers
48 views

Scale independent forecast error metric that works with changing signs

I am trying to analyze a quite large (~25,000 rows) dataset of cash flow forecasts. Receipts and expenses are aggregated, thus I may end up with the following data: ...
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1answer
103 views

Bootstrapping approach: how is the resampled sample chosen?

Bootstrapping approach is based on the assumption that the sample is the population. Then, a resampling of the sample is done, replacing the individuals of the population by chance. The number of the ...
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1answer
50 views

Establishing the lack of randomness in lottery number selection

Related to this question, if I have 1500 or so jackpot results from a 6/49 lottery (numbers drawn, number of winners and prize per jackpot winner), how can I demonstrate that some numbers are less ...
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0answers
43 views

Does confirmatory = inferential, and exploratory = descriptive analysis / statistics?

Reading this webpage, I wonder: Are confirmatory analysis / statistics and inferential analysis / statistics the same concept? Are exploratory analysis / statistics and descriptive analysis / ...
6
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2answers
256 views

Is confirmatory vs exploratory statistics “induction vs deduction”?

This webpage says: Inferential Statistics - Deductive Approach Descriptive Statistics - Inductive Approach But I doubt it. If I understand correctly, Inferential Statistics is "given ...
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2answers
49 views

Range of a centered, reduced sample drawn from a bounded domain

Assume you draw $N$ values from a bounded set, say $[0, 1]$ without loss of generality. If I am right, the centered values $X-m$ will remain in range $[{1\over N}-1, 1-{1\over N}]$ (by considering ...
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0answers
17 views

Measures of consistency and magnitude for hourly data?

I have 3 months of data, collected on an hourly basis, that measures how many events (0-10k) occured in each hour. What is the most scientifically rigourous means by which I can generate statistics ...
3
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1answer
86 views

Generate two variables with precise pre-specified correlation

I want to generate two variables with (pseudo-) random numbers with an exact pearson's r. How do I do that? Python and/or R solutions would be nice! I am able to generate random data that ...
1
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1answer
75 views

Problem with identifying outliers

I'm running a biological experiment with rodents, have two groups (each consists of 26 animals), where one is treated with a chemical, and one is control (saline). In one variable, there doesn't seem ...
0
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3answers
137 views

Descriptive and Inferential vs Parametric and Non-Parametric Statistics

Are the concepts of descriptive vs inferential statistics and parametric vs non-parametric statistics orthogonal? As in, can we have a descriptive parametric statistic or a descriptive non-parametric ...
0
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1answer
52 views

Several items for one construct

I am a dummy in statistics but need to accomplish some simple survey analyses. My question is: if I have several questions (items) for one construct (say, questions JS1-JS3 for job satisfaction) with ...
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0answers
22 views

Exponentially weighted average of data stream variance

For modeling a sequence of data, I once heard the technical term of "exponentially weighted average of the data stream variance". It is defined recursively as I am not clear why does this recursive ...
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1answer
95 views

Comparing the variability of two different large data sets

I have two data sets, one data set contains value in the range of 10,000- 1,000,000 and other data set contains the value between 1,000-10,000. I want to compare the variability means,which data has ...
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0answers
33 views

statistical test for sequence of data

There is a sequence of data. It might have different types of trend, i.e., increasing, decreasing, and even cycling pattern. But there is an assumption that these trends should be smooth. (maybe not ...
1
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1answer
69 views

Prevalence conversion to effect size in meta-analysis

I'm used to thinking about meta-analyses in terms of evaluating the impact of an IV on an outcome of interest (ex: relationship between a teacher's level of self-confidence and student outcomes), and ...
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0answers
14 views

What are the most accurate athletic performance indicators based on scores?

I want to generate statistics for a sport I'm doing. I am collecting data such as my scores and instances in which I miss. Based on this, I calculated averages for my overall performance and for when ...
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2answers
79 views

average length of stay in hospital calculation

I need to calculate the average LOS (Length Of Stay) over 15 years. My formula is the following: ...
4
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2answers
73 views

Do M-estimators and L-estimators overlap?

In my self-study, I have read the wikipedia entries and some books in regards to M-estimators and L-estimators. I understand that M-estimators are so called "M" because they "Maximize" the likelihood ...
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0answers
39 views

Variance partition coefficient

I want to arrive at a measure that tells me how much of the total variance of a variable is due to the differences between units (between variance) rather than due to differences across time for the ...
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0answers
13 views

getting the variance of a set composed of a group of subsets [duplicate]

I have a data set $\mathcal{S}$, which is composed of several subset as $\mathcal{S}=\{S_1,...S_i,...S_n\}$ Each $S_i$ has its own mean $\mu_i$, variance $\sigma_i$, and size $\|S_i\|$. Is there a ...
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0answers
56 views

Statistical Problem

A psychiatrist hires you to study whether her clients self-disclosed more while sitting in an easy chair or lying down on a couch. All clients had previously agreed to allow the sessions to be ...
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0answers
29 views

Why is the scatter diagram always symmetric around the SD line?

This may seem like a dumb/vague question. When you draw a line of slope $\frac{\sigma_y}{\sigma_x}$, why is this line the major axis of the scatter-diagram ellipse? Is this some property of the ...
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1answer
35 views

Question regarding these two regressions from Stata [closed]

the variables in these regressios are: gpi: Gross Private Investments gps: Gross Private Savings Year, Dummy variables: recession81, recession07 I have regressed gpi on gps year recession81 ...
0
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1answer
72 views

graphical and statistical approach to evaluate the skewness and kurtosis of a data set

In practice, we may always be asked to check the skewness and kurtosis of a data set. I have two questions. Given a probability distribution, how can we determine/evaluate the skewness and kurtosis ...
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0answers
49 views

Predicting Data. [closed]

I have this data: ...
2
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1answer
102 views

Retrieving minimum width that contains specified fraction of all values

I'd like to find the min/max boundaries of a sliding window of minimum size that contains a certain fraction of the total number of elements in an array or collection of numbers. Example: taking ...
2
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0answers
185 views

Exponential regression: calculating p-value and F significance

I have a set of independent data and dependent data $(X,Y)$, where I would like to do an exponential regression to obtain its p-value and significant $F$ (already obtained $R^2$ and also the ...
4
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0answers
79 views

Who is the best writer among statisticians? [closed]

I'd like to learn their writing style. Could you recommend a good writer statistician?
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2answers
420 views

Interpretation of descriptive statistics for dummy variable

How can I describe descriptive statistics for a dummy variable (gender of worker in a shop)? Let's say this is the info that I have: ...
8
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4answers
1k views

What is the difference between descriptive and inferential statistics?

My understanding was that descriptive statistics quantitatively described features of a data sample, while inferential statistics made inferences about the populations from which samples were drawn. ...
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3answers
90 views

Frequency Distribution

I have a question that is very important to me related to the book Basic Statistics for Business and Economics for organizing data into a frequency distribution: Step 1: Decide on the number of ...
5
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0answers
169 views

How to understand the correlation coefficient formula?

Can anyone help me understand the Pearson correlation formula? the sample $r$ = the mean of the products of the standard scores of variables $X$ and $Y$. I kind of understand why they need to ...
1
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0answers
83 views

Non-parametric z-score for comparison of outliers/extreme values across set of non-normal distributions

I have a network and for each node in the network I am calculating a certain property, essentially its 'connectedness' to a set of source nodes. In order to identify nodes which are better connected ...
1
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0answers
19 views

Given a matrix, each row with a list of numbers, find the most variable rows with an “interesting” pattern

I have a file that can be considered as a matrix with each row representing a measurement of gene expression of different samples (each column is a sample). I want to find those genes with the most ...
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0answers
46 views

Comparing two sets of data

I have a research on the effectiveness of the new curriculum for our school. One of my indicators is the students' academic standing (passing/failure percentages). Available data for the new ...
2
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1answer
125 views

What is this horizontal point & confidence graph called?

From page 166 of the Open Intro to Stats, what is this type of graph called? It represents 25 point estimates of a mean, together with their confidence intervals, centered around the actual population ...
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0answers
38 views

Compute sample size for a retrospective descriptive study

I am reviewing records that span 15 years. Latest data about the condition I am studying shows that it's prevalence is 3.6 per 100,000. I wish to show the characteristics of the patients in 4 ...
4
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2answers
128 views

Computing confidence Intervals of ratio of correlated variables

Say I have $n$ independent observation of two random variables $x$ and $y$, which may be correlated, and I want to estimate $r=E[x/y]$. I can use $\bar{r}=\sum_i \frac{x_i}{y_i}$ to estimate $r$ but ...
0
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0answers
85 views

Explaining the difference between baseline data and subsequent experiment data if 1.00 is baseline

I have what I guess is a simple question really and it's probably as much about the English language as about stats. I should explain that this isn't my strong point at all but I have to write up ...
3
votes
1answer
88 views

Descriptive statistics for dates

I have a series of timestamps (expressed as Unix time) representing certain dates when an event happened. I want to analyze these timestamps to find information such as: average time between events ...
3
votes
1answer
281 views

Cronbach's alpha negative result

What should I do if I am getting negative results for Cronbach's alpha? Is there anyway to adjust it?