Questions tagged [descriptive-statistics]

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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12 views

Why under an exponentially weighted moving average do volatility forecasts evolve more slowly over time if the decay factor λ tends towards unity?

For λ close to 1 volatility will evolve slowly over time, whereas volatility responds more rapidly when lambda is much smaller than unity. Conceptually, why is this the case?
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Problem of interpretation of Matlab's pca [closed]

I have generated 500 realizations of a Gaussian random process (with 501 observations) whose random variables are standard and the covariance kernel is also gaussian. When I perform the Karhunen-...
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36 views

Does mean deviation from mean depend on change of origin and scale?

I know that SD depends on change of scale and not on change of origin. what about mean deviation? Mean deviation from mean = $\frac{\sum|X_{i}- \overline X|}{N}$.
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39 views

Linear regression with stochastic gradient descent p-values

Is there any way to get summary statistics (p-value specifically) for the results of a multivariate linear regression ($y = X\beta + \epsilon)$ using gradient descent? Most online library ...
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37 views

intuition behind SD+

so i was reading statistics by Freedman and in the section where he describes the t-test he goes on to explain why we would use the SD+ instead of the regular SD to calculate the S.E with the sample ...
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2answers
34 views

Which statistical test to use for binned data?

I researched for hours but cannot find the direction for the right test to use. I have a frequency distribution which shows bins on the x-axis that contain amount spent: 0-5\$ 6\$-10\$ greater than ...
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31 views

Finding The Median

I am a first year student. I have had some exposure to statistics, but I do not know very much. Is there is a statistical method to find the median of marks given only the average of the marks and the ...
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48 views

Standard deviation for proportion with huge denominator

My question involves finding the standard deviation of a ratio when the denominator is huge. The standard formula $$\sqrt{\frac{p(1−p)}{n}}$$ yields a number that is almost zero. The context is ...
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25 views

Can mean standard error be transformed and remain interpretable?

Suppose I collect a two random sample from separate populations Sample 1 has: $$ \bar{x}_1 = A \\ SE(\bar{x}_{1}) = C $$ Sample 2 has: $$ \bar{x}_2 = K \\ SE(\bar{x}_{2}) = N $$ I am interested in ...
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Association between three categorical variables [closed]

Forgive me if this is a silly stats question. I have three nominal variables which describe yes/no for growth of bacteria. They are three different sample types (infant, poultry and floor surface). ...
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22 views

What statistics can I use to describe the shape of a time series?

I want to apply a clustering algorithm to some time series datasets. I've tried DTW, but it hasn't quite achieved what I want (which is to cluster similarly behaving series such that I can tune ...
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11 views

When to Throw out a Respondent (Likert data)

I have a dataset of Likert-type responses, with a few nonresponses throughout. However, one respondent only answered half of the items (basically stopping halfway through). Should a respondent like ...
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How to find association between time spent and capital raised

I have a data set that I would like to analyse in order to determine the most efficient timeframe to fall within when meeting with clients (in terms of capital formed): ...
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How do you compute Cross Correlation,Coherence and Mean Dealy?

This is my second time of asking question here, I am sorry if my question is trivial. I have been researching about economic forcasting using NBER type of analysis. It says about computing Cross ...
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28 views

What type of graphic will be suitable for 3 continuous vs 1 categorical variable [closed]

I want to create a graphic to explore relationship between 3 continuous and 1 categorical variable. I have 2 different examples I want to investigate. 1- the numeric variables are num of bedrooms ...
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8 views

test for homogeneity and heterogeneity in clustering

I want to check if there is a way (or test) to verify homogeneity among and heterogeneity between clusters, besides the almost 30 clustering indices that are available (see NbClust). I am also aware ...
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Summary statistics for bipartite networks

I have a large bipartite network that I would like to summarise. So far, I have found the following summary statistics: Degree centrality Graph density Modularity Nestedness I have not found a ...
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Converting the standard deviation of an averaged score to the standard deviation of a total score

I need to obtain the standard deviation of a total score on a 3-item scale that has been tested on a non-clinical population. The total score is calculated by summing scores for the three questions ...
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can I use chow test

I have a question about chow test. Thanks in advance. I have read a lot about chow test to know that it is most frequently used in structural change dataset. The full dataset was split into two ...
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Benchmarking Analysis (statistical approach)

Im looking for sources in order to perform some kind of statistical analysis applied to Benchmarking, i.e., "market analysis" where I'm measuring the performance of a company's products, services, or ...
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47 views

compare neighbourhood value with the mean value across all neighbourhoods in the city

I have a dataset with all neighbourhoods in a city and their poverty rates. I would like to be able to create a vizualization that enables the user to select individual neighbourhoods and find out ...
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How to compare two statistical distributions with unavailability measurements?

I have two different measuring instruments to evaulate if an electronic device is working or not. These instruments provide a working/not-working reading each day and at the end of the month I compute ...
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20 views

Omission of variable in regression model

I am currently solving a question about the omission of variables in a regression model. The question says that $R^2$ decreases after two variables are omitted in the model; I understand this part. ...
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4 views

hoc test and pearson corelation

Please can you help me how to report post hoc multiple comparison? is it write to report them in that way (M=...., SD=......), i wrote them in that way. And another question how can I report a ...
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Scoring the difference between a family of distributions and a test distribution

Let's suppose we have a random model that I can sample to generate distributions of a certain 1D variable. I want to score the distance of a test distribution to the model in question. The distance ...
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8 views

Descriptive statistics for complementary random variables

I have two datasets, each one contains 157 images of microscopic field processed with a different preparation tecnique. My task is to show if there any differences like cells density, distribution and ...
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35 views

What does range in descriptive statistics mean

What does high range in my variable mean??. If I have a variable whose range is less ,what does it mean??
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27 views

T-test unknown or known standard deviation?

One week ago I performed the following two experiments: 1) I made a tensile test on 30 steel wires. These wires have not been through a surface treatment. The maximum load is (in average) 28 Newton, ...
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29 views

How to calculate weighted average of hourly sales in a day

I have hourly sales data & want to aggregate it to a day level. Out of 24 hours, we are classifying 6 hrs as peak hours and 18 hrs as non-peak. Assume peak hr sales for a day as: $X_1,X_2,\ldots,...
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43 views

What is this “%variance” formula doing?

I'm new to a job and they are asking me to calculate '%variance' with the following formula: $$ \frac{100\big(\frac{\bar{x} - \text{min}(x)}{\bar{x}}\big) + 100\big(\frac{\bar{x} - \text{max}(x)}{\...
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11 views

Correct order for computing standard error of the mean of means

Good afternoon, I read some related questions but there is still some things I can't quite wrap my head around. Let's say I want to average some time series over X subjects, Y channels, and, ...
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33 views

Unit Root Testing

I am having some troubles with the unit root test. The are some concepts that I do not fully understand. Could you please tell me if what I write in the following four passages is correct? I am new to ...
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15 views

Impact evaluation statistical technique

I am new to much of the impact evaluation world and trying to learn it on my own from the internet. I am looking for some advice and help from some of you on a study I am conducting. It is a small ...
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66 views

Statistical test for multiple reponses?

I ran a survey and one question was to indicate which accommodation (hotels, apartment, b&b, ...) respondents prefer when travelling. Thery were allowed to select more than one option. The survey ...
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43 views

How to make sure if the residuals are normally distributed? [duplicate]

Hello, I have a fairly big dataset containing 11000 data points. I am doing a ANOVA for my traits. But before that I have to make sure if the residuals are normally distributed or not. So, I did a ...
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How to infer the distribution of a statistic (Bayesian inference?)

I have a list of approximately 30,000 venues in a major US city. These venues hold all kinds of events, sports, conferences, concerts etc. I want to know the distribution of the 'capacity' of these ...
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1answer
11 views

Coeffcient of variation(CV) with time

I am using an equation that predicts chloride content in concrete at a certain time. All my parameters are random variables. The problem is that as time increases my mean increases and standard ...
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1answer
36 views

Descriptive text from non-standard quantile plot [closed]

I don't think this type of plot has a name, but as the legend shows, the shades of gray represents the quantile distribution of repeated temperature measurements, taken on the same calendar day over ...
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14 views

Likelihood of an event based on Confidence limits

A simple problem I can't figure out. Suppose at confidence level 99.9, there is a likelihood of loss in a 1 in 1000 years. What is the likelihood of loss if confidence level is 60? Any idea how to ...
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1answer
26 views

Identify and remove false positives

I have a set of points that represents events in a process, some of them are false positives. Visually, the false positives are kind of isolated from the rest, as you see in the image. Is there a way ...
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15 views

How to compare or evaluate different ratings

First of all, I would like to state that English is not my first language so apologize me if I use the wrong terminologies. In our company we collect reviews for our branches, so after each client's ...
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127 views

How to automate time series analysis/monitor (descriptive)?

For example, here is a traffic graph from google analytics: You can see that first there is a spike, and then a long plateau time, and then increase to a slightly high stage (but more volatile), and ...
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38 views

How to interpret a negative intercept with summary lmer?

I found a negative intercept in the fixed effect of the summary of my model and I do not know how to interpret the results of the variables. Here is my model : model_velocity_HL <- lmer(PC1~HL*...
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23 views

A good measure for skewed values

I have a table with the list of values as shown below. A Model Number is like a parent Disease. The below table can be read as Patients under Model Number 200(Stroke) are 2.456 more likely to have ...
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26 views

Pooling descriptive statistics of categorical variables after multiple imputation

I am doing multiple imputation using the MICE package on R. My dataset consists of both categorical and continuous variables. After doing say 20 imputations, how should I go about pooling together the ...
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2answers
71 views

Mean and variance of $Y = \cos(bX)$ when $X$ has a Gaussian distribution

How can we find the mean and the variance (not using a software tool) of $Y = \cos(bX)$, when $b$ is a non-zero constant and $X$ has a Gaussian distribution?
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33 views

Choosing appropriate statistical tests

I am trying to run stats on medical treatment data and would like your guys and girls help Goal: Comparing two trends of annual percentages for statistical significance. Is one decreasing due to the ...
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19 views

Comparing the First Names in two population samples

I'm not great at stats and hope for a bit of help ... I have two sets of peoples first and last names the first group has about 5000 unique first and last names and the second about 300. When I ...
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20 views

Creating a custom metric based on diverse feature scalse

I would like to create a custom metric that takes into account multiple features and produces a certain score. However, the issue is that I have data that has many different data types, such as ...
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34 views

Linear Regression confidence interval bounds

When performing a linear regression we first get a slope and intercept that is the best fit. How do we compute the confidence interval for predicted values? Here's an example: ...