# 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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### Difference between Cross-Sectional and Nested Case-Control Samples in Cohort Studies

I have a question regarding the cross-sectional sample from the most recent visit and the nested case-control sample extracted from a cohort study, especially when the exposure of interest was ...
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### How does Minitab Calculate UCL/LCL [closed]

This is a very basic question, but the UCL/LCL of the chart doesn't line up with the UCL/LCL I would calculate and I'd like to understand why. Based on the descriptive statistics, std dev is 13.59, ...
578 views

### average revenue per user increases each country but decreases when combined

I'm trying to figure out what could be some reasons when we do the AB testing we're seeing average revenue per user increases for each country but when we calculate the overall average revenue per ...
35 views

### Find correlation from biased observations

I have a set of observations of a variable Z (shown as the colormap) as a function of two other variables A and B. I want to study how Z varies with respect to A, B, and both A and B (eg. if A ...
1 vote
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### Regression when multiple observations per individual but final result is the same

I'm very new to data analysis. I'm trying to find the causal effect of seating row and laptop use on grades at a specific university. I have data from 15 introductory economics lecture sessions ...
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### What is a good metric for agreement in this problem?

Suppose I have a dataset that needs annotations. I have about $5000$ total $x$ values, and annotations by humans are needed to create $y$ values. $y$ takes a value in $\{0, 1\}$. For example, consider ...
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### Error Bars for Incidence of a Rare Medical Complication

I am making a plot of the incidence of a medical complication by the drug dose used. The incidence is very small, and so I am getting huge error bars using standard deviation-based methods, even ...
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### Need help with chi-square test interpretation with adjusted residuals

I have conducted multiple chi-square tests to compare 3 customer segments (1 cat variable, 3 groups) on different categorical variables. As the chi-square tests are not 2×2, I have asked SPSS to ...
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### Help me understand Z coefficients

When working with sample size equations, one uses the Z coefficients Z$\alpha$ and Z$\beta$ which are the Z-coefficient for Type I and Type II error rates. These coefficients are from the standard ...
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314 views

### Cronbach alpha - descriptive statistics

I researched thinking styles based on Sternberg's Investment Theory. I used a TSI questionnaire that measures preferences in thinking styles. The problem is that I got low scores of Cronbach's alpha ...
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### What weight to use for using NAMCS and NHAMCS together?

I am interested in analyzing the total prescription of aspirin in NAMCS and NHAMCS (https://www.cdc.gov/nchs/ahcd/index.htm) during a given year for all visits. NAMCS and NHAMCS each had a weight and ...
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1 vote
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### Developing a Confidence Interval of Density Functions for Uniform Periods in Seasonal Time Series Data

Suppose I have a set of observational data as a time series where the observations are collected at uniform interval over the course of several years. The data exhibits seasonality over the course of ...
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### Summary statistics (mean and standard error) of split plot nested design- using R

I have a study with a split plot design where every season (wet and dry) we sampled for 3 years at 8 sites. At each site (fixed factor), we have plots (nested within sites) and then we have subplots ...
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### How to interpret a regression with years on the LHS

I would like to know how I can interpret the coefficients in a regression when the dependent variable is years. For example, suppose I am interested in the year different cities received a new Apple ...
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### How do I determine how well a person does on average compared to previous work done in their same position?

I'm currently leading a group of missionaries and I want to find out how well each missionary is doing compared to the average in their area. Each area has a historical data of how well it's performed....
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### Can you create an age structure of population, if the age was established using multiple different methods?

I want to analyse a age structure of my sample. However, I was not given the ages themselves and instead had to establish them using multiple methods with various coefficients of determination (not ...
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42 views

### How to find a consistency index for a binary variable?

I am working on a project where there are 2 variables to monitor, say sales (actual) and projected sales (target). The sales ...
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### Methods for describing higher level categories (aggregate summarized values or all original values)?

Let's say there is this questionnaire-based study: A restaurant serves these 2 categories: Food ("f") and Drink ("d"). Each respectively has hamburger (f1), fries (f2), and fried ...
1k views

### Can I use p-values without hypothesis?

I have been working on my Master's Thesis which included a survey and its results have been put through various tests. The unusual thing about my Thesis is that I have no hypotheses at all, making it ...
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### How do we decide the sample size we need for ensuring reliability for a test?

There is a test consisting of 6 questions and additional sub-Qs. The test was translated into another language and the questions were adapted, but the reliability of the test was never assessed. The ...
53 views

### Different notions of width for multivariate Gaussian distribution [closed]

Given a multivariate Gaussian distribution $\mathcal{N}(\mu, \Sigma)$ where $\mu$ is a real vector and $\Sigma$ an associated covariance matrix, I am looking for a good notion of width. There seem to ...
1 vote
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### Probability of Random variable less than a quantity containing random variable [closed]

What is the probability of the following: $P\left(Z_j>\frac{\epsilon}{a_j*R}\left(\sum^{M}_{m=j+1} ~ a_m*R*X_m+1\right)\right)$ where $Z_j$ and $X_m$ are independent and identically distributed ...
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### What do these Wilcoxon values tell me?

I did a pre and post-test with a small number of students ($n=12$).These values came after a science intervention that took $4$ weeks. I used a Wilcoxon test for 2 related samples as there was not a ...
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### How to calculate weighted mean when your sample is unweighted, but you know your population

Lets say I have the following sample data. ...
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1 vote
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### BEST POSSIBLE WAY to determine significantly high values within zero-inflated univariate continuous distributions

I have more than 50 different distributions, corresponding to 50 different kind of customers, who spend their money in a certain way within a period, being this amount the single variable of interest. ...
1 vote
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### Managing Daily Quotas with Complex Equation for Resource Allocation

I have a complex resource allocation problem where I need to manage specific quantities while adhering to a daily quota of 3000 tonnes. The allocation is based on various variables, and I'm looking ...
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### Help determining which statistics to use

Forgive me as I am a novice. I have done a training for a group and wanted to calculate some stats on the percentage of improvement of knowledge and understanding based on participant survey answers. ...
205 views

### How can I calculate a relative measure of change for data series that can include zero?

I have a series of data points representing the number of OKs for a test. For each data point, I want to calculate by how much its value changed compared to the preceding value, and I need this ...
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### Example of statistical experiment in which the statistical unit is time

Could you give me some examples of statistical experiment/analysis in which the statistical unit is the time? If I conduct a study on the number of people who have attended a bachelor degree over time,...
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### How can I identify a distribution?

I have data that looks like this when I plot a histogram. I have this data for several years (this is a count of values per group) and each year looks very similar. Is there a way that I can: more ...
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### Classification problem: Choosing medication to prevent side effects based on patient characteristics

I need your help to solve a classification problem. Typically, we have independent variables and we try to predict a target variable. I have a different type of problem to solve. In my case, let's ...
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### F1 score for multiple datasets

I am testing my algorithm on 20 different datasets. So, as a result I derived 20 F1 scores based on precision and recall for each run (dataset). Is there any way to combine all these 20 F1 scores into ...
22 views

### How to describe data? With p-value or without it?

I have health related data sets such as age specific mortality of all deaths in specified areas and time periods. Since I have anonymised records for each event, I can calculate indicators of central ...
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### how to properly calculate statistics with data (time series) repeated in the same time stamp

We have made almost 400 laser experiments where the measurements are done through a photocell, registering voltage variations corresponding to variations in the intensity of the laser beam. When the ...
18 views

### Determining comparable individual performance within a team sport

i have collated a significant body data for a local badminton league (> 20000 indvidual games) and while i have the means to extract data on a: per player per couple per team per club per season ...
55 views

### Comparing pre and post treatment data - best statistical test?

I am analysing a range of clinical outcomes for a drug treatment and need to compare the values pre and post treatment - I’m using excel to do this and have found that for most of my outcomes the data ...
53 views

### Variance of sampling distribution

$\operatorname{Var}(\bar X)=\sigma^2/n$ is the formula of variance. I want to check my understanding of this concept. Suppose I want to compute the mean household income of a given city. I collect all ...
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1 vote
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### If we know the exact value of the population parameter , is there any point in doing the hypothesis testing? [duplicate]

Question - In a year there are 956 births in a town A of which 52.5% were males, while in town A and B combined, this proportion in a total of 1406 births was 0.496. Is there any significant ...
1 vote
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### Was my path of statistical data analysis correct/logical? [closed]

I analyse physicochemical data from the river and two rows of wells - one located closer and the other further from the river. The study's main aim is to investigate the variability (or heterogeneity)...
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### Which observations should I use for my panel data analysis?

I am currently working on my Master's thesis and for this I would like to examine the impact of the geographical location of Mutual Funds on their performance. For this I have panel data of mutual ...
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### Guidance for statistical analysis on academic collaborations [closed]

I am currently engaged in a research project involving data analysis in the field of academic publications and author collaborations. The dataset I'm working with includes information such as ...
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### Can LASSO still perform regularization on summarized data?

Currently, we are trying to predict future revenue from existing users. We use the revenue collected after 14 days of membership to predict 3 year membership. We train the model and make predictions ...
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### Range of correlation between two stacked pairs of data

Similar questions have been asked before where we have Cor(X,Y) and Cor(X,Z) and we want to find out the range of correlations of a linear combination of X & Z with Y. Or a third correlation: (X,Z)...
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### Should I be concerned of Over-Optimism in Nested Cross Validation with Multiple Scoring Criteria?

Suppose I am using Nested CV to estimate the generalized error of a model and a set of hyperparameters. I have chosen two scoring metrics of interest: Brier Score and AUC, because I want to get an ...
165 views

### Normalizing Euclidean distance by the length of the vectors [closed]

Suppose I have 4 vectors, the first 2 vectors are of length 4 and the last 2 vectors are of length 400. all values in the vectors range from 0.5 to 0.6. The Euclidean distance between the last 2 ...
1 vote
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### ordinal data negatively skewed. Help me :( [closed]

I'm working on my masters dissertation. Please help me this is my very first ever quantitative research and my submission deadline is very soon and my brain is literally melting into soup :( 1- Data ...
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1 vote
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### How to find an "upper margin" for data on visits

For a handful of store locations, I have data on each entrance and exit time. I have counted the total num of people at a store at any given minute. I am trying to find out the values for which the ...
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1 vote
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### How can I perform statistical analysis, (PCA sPLS-DA) etc on a dataset which has many missing values? [closed]

I have a dataset of mass spec analysis which was sent to me in 200 excel files. Importing into R, I get a dataframe that looks like this: | Unique Sample ID | Chemical Name | Concentration | | --------...
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### Statistical explanation for a way to group data

I would like to know if there is any statistical explanation on why it would be a good idea to group some data into the following way: find the maximum ($\max$), minimum ($\min$), mean ($m$) and ...
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Let’s say that $X$, $Y$ and $Z$ have some fat tailed distribution, $X$ and $Y$ are stock returns, i.e., the sample set can have both positive and negative values. While $Z$ is some random variable ...