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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14 views

Which statistics result can be derived from this data?

I have 2 information sheets. 1st one is monthly period data on x-axis(2011 Jan to 2014 December) and # of lung cancer patients divided by population on that period multiplied by 100 on y axis. ...
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27 views

What is the standard way to distinguish the errors associated with sampling and measurement in statistics?

This is probably a very basic, yet not easy, question in applied science. I was just wondering, what are usually the standard ways to deal with it? Any pointers to further references are greatly ...
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35 views

Sample size when using GPS-trackers to analyze movement of reindeers

If one were to try and analyze the movement of ~2 500 reindeers before and after a (man-made) change in landscape have occured. Specifically how spread out the herd is, both as a whole and if there ...
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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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4 views

Find the expected frequency of some state in a state sequence of length N given a transition matrix M

I can represent stochastically-articulated sequences of states using a transition matrix M where a given entry in cell (i,j) corresponds to the probability of state j given that the current (or, most ...
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2answers
65 views

How measuring the proportion of object in several classes?

I have 4 classes and I want to classify objects in each class. I have an arbitrary number of objects indexed from $1$ to $n$. My problem is, when $n$ varies, the proportion can change a lot. For ...
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19 views

Cronbach's alpha, When to use it

I am a bit confused about the use of Cronbach Alpha. I have a questionnaire I administered to 20 respondents. I have gotten the data back from the survey. I am told I need to do an Internal ...
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20 views

Calculation of median: Why are means of ranks not used for it?

in order to calculate the median, I have to sort the data in a ascending/descending order. Each value gets a rank so that I can (for uneven samples) look up the value that rank X = (n + 1)/2 has, ...
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20 views

Regression not sure

My early research shows that after giving voice therapy children improve their phonetic production- faster reaction times ( I had 10 participants who named 20 items pre and 20 post therapy). However, ...
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1answer
38 views

best arima model in R

I'm new to R. I'm trying to fit an ARIMA model to a large time series. The best model found with auto.arima is ARIMA(0,0,5). The residuals plotted with tsdisplay are looking like below. Can someone ...
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1answer
44 views

Explanation of the different variable types in statistics?

One thing that has always tripped me up when trying to learn new methods in statistics is understanding what type of features/variables can this method be applied to. The variable types that ...
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24 views

Which test(s) to use?

I’m having a dataset that needs to be analyzed but I’m a bit worried about picking the appropriate test(s). It’s been a while since I last really used statistics and SPSS. Therefore I would kindly ...
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23 views

1 IV, two levels; 2 DVs (one post-test only, one pre-test & post-test). Have some ideas but unsure. Cliche question but:What stats test to use?

I'm working on a proposal and trying to get my stats tests right. Been doing some reading and while I'm beginning to get a better grasp of things, I'm still a little puzzled as to what stats test to ...
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1answer
64 views

Correlation between a percentage and a real number

I have two datasets, one containing the percentage of people with flu and one which has the number of searches for Tea-recipes in google. Problem is, I get different results when i choose to include ...
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4answers
504 views

Percentile vs quantile vs quartile

What is the difference between the three terms below? percentile quantile quartile
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15 views

Standardizing IQR

Suppose I have a data set like the following Q1 Median Q3 IQR 10 20 30 20 15 20 35 20 100 200 300 200 I don't have the actual data ...
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30 views

How should population sample characteristics be presented for a small sample size?

I'm performing a clinical trial and have enrolled 16 patients, of which 3 had to be excluded. I suppose it would be relevant to present some characteristics of the included patients, e.g. age, weight, ...
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26 views

Finding descriptive statistics on particular days on the time series

I got a time series of returns for the last 15 years. I would like to extract the descriptive statistics on last Thursday of every month. Suppose, if I add a filter for last Thursday of every month ...
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9 views

Relative measure of a questionnare

I have a psychological questionnaire which deals with people's satisfaction from life. The questionnaire is build from several questions, each has a weight (how many points it is "worth"). The total ...
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25 views

Should I normalize my variables for a descriptive logistic regression?

I'm running a logistic regression in order to descriptively analyze the relationship between my independent and dependent variables. As I understand it, it's not mathematically necessary to normalize ...
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37 views

Combining multiple metrics to provide comparisons/ranking of k objects [Question and Reference Request]

Collecting $n$ metrics about $k$ objects Suppose I collect $n$ metrics about $k$ objects. I am looking into valid ways to compare the $k$ objects so they can be "ranked". I think this may be ...
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1answer
45 views

Standard deviation of a casino's profit

For the following question, I've determined the mean to be \$0.20, but how do I determine the standard deviation? A slot machine at a casino pays out an average of \$0.9, with a standard ...
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1answer
40 views

Why pnorm function and sum of dnorm function differs for same input?

Data is height of men in 'inches'. Mean is 70. SD is 3.3 I wanted to compute the probability of men whose height is in between 69 inches and 74 inches. The following methods gave me different ...
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3answers
49 views

Non-normal univariate distribution — how to define “low” to “high” subsets of values?

Sorry for the dumb question: it's been a million years since I took basic stats. I have a set of 48, non-normally distributed values ranging from 1 to 100. I'd like to be able to apply a (valid) ...
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25 views

suitable statistics to replace box plot [closed]

I am applying few classification methods on a set of images. Currently, I have experimental results in box-plots and want some statistical method to report them in my dissertation. Problem ...
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27 views

Issues with derivative of a copula density

Suppose I have a bivariate copula density with marginals $F(X)$ ($F(X)$ is normal with parameters $\mu_1$, $\sigma_1^2$) and $G(Y)$ ($G(Y)$ is normal with parameters $\mu_2$ and $\sigma_2^2$). I want ...
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47 views

Estimating probability distribution function of data stream

Although a similar question exists, I couldn't find my answer. I'm not a statistician hence please neglect if some terminologies aren't correct and let me know if I am interpreting something wrong. ...
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22 views

Can you calculate descriptive statistics (SD, SE particularly) from percentages and ratios?

I'm a cell biologist and a lot of my data is expressed as a fraction (percentage) of the total number of cells in a single experiment in a number of separate categories (generally 5 or so). The number ...
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1answer
28 views

What's my population? Is this Descriptive or Inferential?

I have a list of employees at a company. I want to show some comparison of some demographics (say, %female) of those who have left the company and those who have stayed with the company. However, I ...
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1answer
226 views

Is the following dataset possible?

"Is it possible to create a data set where $\bar{x}=30.0$, range $R=10$ (meaning the max-min=10), and variance $s^2=40.0$?" I feel sort of dumb asking this question, but I'm not quite sure I'm on the ...
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47 views

Efficient statistical test to compare two multivariate distributions

I am looking for a test to assert the "equality" of two multivariate discrete distributions, $\mathbf{A}=\{A_1,\dots,A_k\}$ and $\mathbf{B}=\{B_1,\dots,B_k\}$ for which I do observe two samples ...
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18 views

Forecasting Prediction Accuracy

Out of 4 error paramters which one is best for evaluating prediction accuracy? Average error Mean absolute error Mean squared error Mean absolute % error why?
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21 views

What is the best way to group countries for graphing world crime statistics?

I am currently working on a project where I have chosen to analyse the frequency of terrorist attacks and their impacts using the global terrorism database (dataset available here: ...
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17 views

Chi-square and subsequent comparisons

I have the following dataset and would like to find out firstly if I'm using the correct tests. The data are hospital admissions data for cause X and admissions data for all admissions. If an ...
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1answer
25 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 ...
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19 views

How to determine the number of employees in a business when sources are inconsistent?

I am analyzing a business survey data. I am interested in the total number of employees of each firm. Specifically, I am interested in: The total number of employees in a specific city, and The ...
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41 views

How to show whether a hypothesis is true or not

I have the following hypothesis: "The higher the number of translation-stable words between a pair of countries, the higher the correlation between the happiness scores of their words". note: ...
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1answer
51 views

Can a truly randomized procedure (e.g. random treatment allocation) result in unbalanced distributions?

Thousands of randomized trials are ongoing or in the planning. These trials rely on randomization procedures (e.g. patients being randomized to either placebo or active drugs) to yield two balanced ...
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3answers
850 views

Do descriptive statistics have p-values?

I'm being asked to find the p-values for descriptive statistics. However, it's my understanding that p-values are for test statistics. If I'm not mistaken, a p-value is the probability of observing a ...
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1answer
32 views

Using counts of a continuous random variable to establish an unknown probability density function

The precision of a given measuring device defines a window over the probability density function of whatever is being measured. For instance, if a measuring tape is precise to 0.1 inches, then the ...
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1answer
73 views

Determining continuous vs discrete data sets?

When I collect data for my work, I get a set like the following: [ 133, 183, 185.16, 188, 143, 128, 135.5, 100.55, 117.96, 95.5 ] These points are part of a ...
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1answer
48 views

Results of 2-sample t-test does not seem intuitive; wrong procedure?

I have data shown below, with a response variable tabulated by hour (x-axis) as well as numerous other factors: larger chart available here I want to see if the colored points (red, light and dark ...
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1answer
38 views

How to compare age across multiple groups?

I have age data on 5 groups, and I would like to compare if one group is significantly older or younger than another. When comparing 2 groups, I can use a 2-sample t-test, but when comparing across ...
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1answer
51 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 ...
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15 views

Using predictive algorithms for descriptive purposes? Correct? Any resources?

Newbie here. I've been learning lots of predictive modeling with R/python using the well-known algorithms: decision trees, random forests, SVM, logistic/linear regression, k-Means, k-NN. But I'm new ...
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2answers
41 views

Compare lists of genes

I have two lists of differentially expressed genes: the list 1 was derived from the universe A of total genes while the list 2 was derived from the universe B of total genes. A number of genes is in ...
2
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1answer
58 views

Describing trend magnitude or detecting trends

I have time series data. One observation per time period, about 10 observations or so. When describing the data (I am interested in descriptive statistics), I'd like to say that there is either a ...
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1answer
74 views

What is the honesty condition for regression trees?

I have a question pertaining to Stefan Wager's "Asymptotic Theory for Random Forests": http://arxiv.org/pdf/1405.0352v1.pdf Wager first states that trees are "fully grown in the sense given training ...
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66 views

Wilcoxon signed rank test - Normalize data or not?

I am comparing my algorithm's performance with other algorithms, for a minimization problem. There are ten different benchmark problems, for which I have computed the average solution quality for all ...
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19 views

Which statistical tests requires one to know the sampling error?

I would like to know which statistical tests requires one to know the sampling error? I am planning on using an existing public online panel that is representative of the UK population by age, gender ...