# 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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### How to characterize a dataset

I know we can compute a correlation matrix for continuous variables in a dataset. However, to summarize the degree of correlations between variables, is it possible to do a mean or something else ...
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### When trying to find the quartiles for discrete data, do we round to the nearest whole number?

I have 2 cases: First, I want to find the first quartile to the set data: 1,2,3,4,5. Normally we calculate the qaurtile as: Now $Q_1 = \frac{2+1}{2} = 1.5$. But they never state if its continuous (i.e....
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### Triangular correlations?

As used in my answer at https://stats.stackexchange.com/a/652022/11887, triangular correlation seems to be a useful concept/terminology that could see more use. But searching I cannot see much use, ...
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### How to adjust a variable by age, sex and BMI

I'm working on a database with almost 300 patients, of which I have their age, sex, BMI and their level of diabetes (which, for the purpose of the study, is stratified into mild, intermediate or ...
1 vote
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### Looking for statistical function to represent data

Say I have a molecule that contains 9 atoms. For each atom, I have calculated the properties as prop_1, prop_2... prop_5 using a certain methodology. To check if the methodology was stable, I ran the ...
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### Can I do weighting on continuous variables?

I have two datasets collected in 2018 and 2023. I was going to check if there's any difference between the two datasets, but the ratio of sex and family size was different from each other (...
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### How can you calculate Q1 and Q3 for even numbers? [duplicate]

I've searched this question everywhere, but I've found different answers and none of them result in the same answer Numpy gave me. I have the following data:[0, 1, 2, 3, 4, 4, 5, 5, 6, 8] When using ...
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1 vote
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### Appropriate significance test for small sample size, unclear (non-normal) distribution

Given data: 30 datapoints in the form of usability scores (System Usability Scale) 2 groups within data (Group 1: 17, group 2: 13, independent, unequal sizes) Objective: See if there is any ...
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1 vote
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### What analysis do I need for 2 Ivs and 2 DVs?

I think I need a MANOVA, but I may need an ANCOVA and then also do an ANOVA within just the experimental group. I think it's a 2x2 factorial independent measures ANOVA within the intervention group. I ...
1 vote
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### Hausman Test Reults Report

I've been working on a research project using a multi-level regression model, and I'm currently figuring out how to present the Hausman test results. I've seen some papers where authors mention doing ...
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### Is considering a specific distribution necessary before computing an average?

Many times, I compute averages of variables without considering distributions at all, and I use those computed averages to represent measures of variables in my data without mentioning specific ...
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### calculating percentage normalisation

Please don't laugh or close this post I am confused as to how I can calculate the percentage normalization occurring post treatment. So, here is a background of the problem, I have reading from ...
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### Reference for Directional Statistics of Plane Orientation

I've got a project I'm working on where I've got the orientation (normal) vectors of planes. These vectors are all within a unit hemisphere where the $z$-coordinate is strictly positive. The ...
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### Analyzing lists and variables of multiple answers

My current issue lies within EMR extracted data for medications. There are multiple variables named: Medication_1, Medication_2, Medication_3, etc... This data may overlap and analyzing each column ...
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### How is this formula derived

I have carried out an experiment with several repeats and my program has returned the values of EC50 and its CI(95%) confidence intervals, LogEC50 and the standard error of (LogEC50). The logs are ...
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### Normalization of absorbance data by fresh weight of samples

A [protocol] says For each sample the absorbance (Abs) reading was divided by the fresh weight of the sample in grams. The results were normalized using an arbitrary value of 1 for the control ...
26 views

### Survival function for a certain population

If the survival function for a certain population is given by $$s(x) = \left( \frac{1}{1+x} \right)^4$$ for $x \ge 0$, how long would you expect a person who is $41$ years old to live? (a) $14$ ...
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### Standardization of summary statistic of group-linked values

Assume that you measure a summary statistic (e.g., arithmetic mean) in measurement windows of a fixed size along a long sequence of values and that these values are grouped into regions belonging to ...
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### OLS Model with Lags - logged coeff

i am building a OLS model using python, where the dependant and independent variables are lagged. This is a form of econometrics model where i want to figure out how much each independent variable ...
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### Comparing one value to mean or median of a group

I have very limited statistical knowledge or experience, so I am looking for some guidance on my approach for statistical analysis. I have a group of 60 values. I am looking to compare the last value ...
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### Should we routinely conduct unsupervised learning when reporting descriptive statistics on data?

A standard approach prior to conducting a predictive or inferential analysis is to report some basic univariate descriptive statistics on the study variables: mean, median, minimum, maximum, variance, ...
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### how to summarize moving average

This question is about how to summarize moving averages. Please assume the values in column Pct are % of people how have negative opinion about vaccine. column MovgAvg is the two year moving average ...
1 vote
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### Which statistical model is suitable?

I have the results of a survey of $n=132$ patients with their socio-economic profile and their spending behavior on mobility-coins (my thesis topic). In the survey, we asked people how they would ...
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### type I error in multiple comparisons summary statistics

I understand type I error can increase if we run 'multiple comparisons'. But does that refer to comparisons within a multi-category variable (or a group variable)? or multiple analyses using the same ...
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1 vote
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### Maximum Likelihood in High Dimensions [closed]

What are some examples of high-dimensional random variables for which MLE are solved using numerical methods because we are unable to explicitly solve the equations nicely? The only example to comes ...
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### Variability of patients in different Hospitals

just to let you know that my statistical background is not very good. I made funnel graphs which shows the effect of polypharmacy against practice size. In the funnel graphs, a dot presents a single ...
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### Should a Better User Engagement Model Keep Outperforming Old Models Across Time?

Context Let's say we are talking about a machine learning model that governs some user interaction (e.g. pricing model, recommendation model etc.) on an app. Let's say model v1 is champion (in ...
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### Is the exponent of the MAD (Median Absolute Deviation) of log transformed Data measuring the relative distance from median in the untransformed data?

I want to confirm whether taking the Exponent of the MAD of Log Transformed Data gives me a measure of relative distance from median of the original untransformed data. So say I have a MAD of 0.2 for ...
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1 vote
26 views

### Degrees of freedom for estimation

In the context of estimators, why is it that in general dividing by the degrees of freedom(instead of the sample size) leads to unbiasedness? I see the value in substituting degrees of freedom for ...
1 vote
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### Percentiles of a distribution of weighted summary statistics

Suppose I have a collection of different independent probability distributions, $\{ P_i(X)\}_{i=1}^N$, each with their own support $I_i$. I know that the $10^{th}$ percentile of a given distribution ...
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### Looking for ideas to improve Weighted Moving Average result

I have two data sets: ...
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### Comparing averages of two groups

Say I want to check if the averages of 2 groups (A and B) are the same. For each member in group A, there are some observations; same applies for group B. If I want to take the average of A and B, I ...
48 views

### Is it possible to calculate a standard deviation from the gini coefficient and mean?

I am looking to create an analysis showing how many people in a given country have more than than X dollars in income. I know the average income, population count, and Gini Coefficient of income ...
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### Is descriptive statistics enough to compare test scores of students in a class?

I am reviewing the theory on hypothesis testing and the book I am reading ("Hypothesis Testing" by Jim Frost) stresses the fact that we do hypothesis testing and inferential statistic when ...
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1 vote
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### How to Evaluate Interaction Effects in Propensity Score-Matched Samples:

Suppose I want to study the association between an exposure X and outcome Y, and I have used the propensity score to match each exposed subject with those unexposed but with similar characteristics ...
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1 vote
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### How many samples should I test to be 95% sure that no error exists?

If I have a million population of products and I will tolerate no error in them. How many samples should I test to be 95% sure that no error exists? I am new to statistics. I know you might need some ...
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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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### 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 ...
50 views

### 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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### 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....