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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Why adjustment is needed when calculating Skewness and Kurtosis?

Some packages such as Mathlab, Minitab and SigmaXL caluclate adjustment for skewness and kurtosis. For example at: https://octave.org/doc/v4.0.1/Descriptive-Statistics.html it is suggested that ...
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How to create the fixed effects model from the data? [closed]

I am working on the data about student's exams scores measured depending on techinque and the day exam was taken. ...
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How to assess economic significance in a log-log OLS model?

I ran an OLS regression in log-log form and got statistical results (coefficients and their standard errors). How can I now assess whether these results are economically significant? I also calculated ...
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what is "moments" in descriptive statistics? [duplicate]

there are central moments and raw moments (about the origin and the scale of the data), which are used to calculate the skewness and kurtosis, so what exactly is moments in a data?? is it in literal ...
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Correlation between binary (true/false) variable(s) and a continuous variable (a real number)

I have four types of binary variables (true or false) and a single continuous variable. I want to analyze the correlation between any of those binary variables with the continuous variable. My dataset ...
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Determining Percentile Ranking of Test Score Given Individual Score, Population Mean, and Standard Deviation

I have recently received an exam grade of 160/200. In addition to this, I have been given the information that the mean score amongst all students was 114.25 and the standard deviation was 45.62. ...
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variance of the difference of two independent variables is the sum of variances

It is said that variance of the difference of two independent variables is the sum of variances (topic - Confidence intervals. Two means. Independent samples) I tried to experiment with small dataset ...
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Statistical analysis (comparison) of time course experiments

I have data sets that represent multiple measurements over time. The data sets come from biological experiments in which we measure something in N individual cells, with around 250 measurements over a ...
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Statistical Data Analysis using "Sum" Function

Most commonly when I hear descriptive data analysis using statistics these following functions are often inclded: Mean Standard Deviation Variance Range Mode Median etc. Is the function "Sum&...
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How to compare subjects/groups with multiple variables which have multiple values?

I would like to get an opinion about comparing groups of subjects that have multiple variables multiple times. I have three groups (A,B,C) divided by their age. Each group has a different number of ...
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n-th quantile for bivariate variable

I generate a 2000 bivariate random samples which are negative correlated. I used np.quantile to generate 10 quantile from this random samples. The related point is marked in the following figure. I am ...
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Linear Regression as a descriptive model?

I understand that linear regression can be used as a descriptive model (also am well aware that the regression coefficients should be interpreted as correlations rather than causation). So I was ...
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Maximum Likelihood Estimation for data with non normal distribution [closed]

I have a set of data (results) that does not follow Normal distribution. In this case, wow can I get Maximum Likelihood Estimation? Thank you very much
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Should I use Mean or Median? [duplicate]

I am analyzing a set of data (results) that does not follow Normal distribution or any known distribution. In this case, is it better to use (mean) or (median) to describe the result? Thanks
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How to calculate the within-pen standard deviation?

For my research, I am investigating the occurrence of tail biting in pigs. I would like to calculate both the overall standard deviation of all pigs, and the within-pen standard deviation. I am not ...
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How to resample members from the population who didn't respond after the survey?

I have used stratified random sampling on population to generate the sample. Now the issue is if after the survey is conducted some of the members in the sample ...
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Statistics to use on Bimodal data

What summary statistics, mean, median, standard deviation, etc. should be used on a skewed, bimodal, dataset and why? These are almost U shaped in a histogram layout with a slight preference for lower ...
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To calculate income gap: use log income or original value

I am tring to calculate a measure of income gap of my individual-level sample (by group) and use it in regressions. What I want to do is to divide the mean income of individuals whose imcome are above ...
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If the variance of two variables are equal, then the covariance is the variance?

If I have two random variables $X$ and $Y$ and their variance is the same, i.e., $Var(X)=Var(Y)$. Does this mean $Var(X)=Var(Y)=Cov(X,Y)$ ?
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How to use RFM along with Predictive model?

I am looking to segment my customers based on their transactional data with us. Based on google search, I came to know about RFM matrix, which records Recency, Frequency and Monetary value-based ...
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Methods for selecting the best variable into the regression model

I have constructed a continuous variable by using two different methods. Now I want to know the variable created under which way is the best and should be included in the model. Some preliminary ...
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How to decompose multiple periodicities present in the data without specifying the period?

I am trying to decompose the periodicities present in a signal into its individual components. Say the following is my signal: You can reproduce the signal using the following code: ...
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What should I check/test when I want to generalize from a sample to the population?

How do I ensure that I'm allowed to generalize findings from a sample to the population? So far, I'm only aware of the standard error. Is this (alone/itself) sufficient or even valid? As the CI is ...
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Another question on population vs. sample

The problem that bugs me can be boiled down to: "What is population? (Really)." This is my thought experiment I've dealing with for a few days. There is a researcher A, who gathers data from ...
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How to calculate sampling error for proportionate sampling?

I have done sampling using Proportionate Stratified Random Sampling. The table below shows the proportion of each groups in the sample and population. This is the formula for Standard Error (...
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What is a good type of transformation to try on this data to get normal distribution?

I've tried a log-transformation but data becomes left-skewed. In general, when data is distributed like this, what is the next best transformation to try if you want to normalize the data?
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What statistical method to use to analyse decrease in energy usage if production is always increasing?

Production at a factory is always increasing (tonelage), and energy (MWh) consumption is directly proportional, which would be a positive correlation. In parallel, there is investment and effort for ...
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Summaring post hoc differences of means for several groups

I have 5 groups with unequal variances. I used a Welch's ANOVA and then a Games-Howell post-hoc analysis to find the pairs that have significant differences. I have a large number of samples in each ...
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Characterizing "aggregatable statistic" with moments

I'm working on a project where I have statistics for several disjoint sets of data and need to use them to compute aggregate statistics for the whole population. An example may help here. Say we have ...
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Variability and mean

I am working with future climate change scenarios and I end up with this question. Is it expected from a statistical perspective that a change in the mean goes hand-in-hand with a change in the ...
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How to check if the sample represents the population data?

The below table is similar to the population ...
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finding central tendency

The following table presents frequency distribution of teachers of 1 year: Rank ----------Frequency Professor ------------7 Assoc Professor ------4 Asst Professor--------3 Instructor -----------5 ...
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Using Pairwise Differences Between Two Conditions as Data (Bayesian)?

Suppose I have measurements for the expression-level of a "gene" from two groups of arbitrary (possibly different) sizes. Maybe one group is a control and the other treated. $x$ = <4.5, 5....
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Confidence interval for multiple samples of ratios of counts (in R)

Data and objective I have count data from two groups, A and B, from across multiple samples. I want to estimate the average ratio of A to B across all samples, along with a confidence interval. Issues ...
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What interval does the median fall into when the values of the numbers before and after the median aren't specified and n is even?

What interval does the median fall into when the values of the numbers before and after the median aren't specified, but are the last and first data points in the intervals sorrounding the median, ...
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Calculating average for each individual or not?

I have a question about how I should organize my data before doing some statistical analyses. In my data, I have a sample of rats for which the level of tear stains and body lesions is measured. They ...
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Flagging bad time series behavior (Pattern Recognition and Outlier Detection)

I want to get some opinions on how to approach the following problem to do with detecting "unhealthy" behavior in time series data (either using a statistical/analytical model or ML/DL, I do ...
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Detection of 'unfair' Bernoulli sequences using run lengths?

I'm rather confused about the following question: Which of the following vectors do you think is actually a random sample of $\mathcal{B}(1, 0.5)$ (Bernoulli) of length 10? $[0,1,1,0,1,0,1,0,1,1]$ and ...
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Test-retest reliability for a test taken twice but with a variable delay between tests

I have a dataset that is composed of a few thousand datapoints, each of which consists of two test results for a participant that were collected when they underwent the test at Time A and Time B. The ...
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Best way to combine categorical variables

I have two categorical variables measuring outdoor time during winter and summer. As I am interested in the overall outdoor time during the whole year, I am thinking about combining the variables. ...
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Statistical power of tests on unequal and known variances vs equal but unknown variances

Suppose you are testing for differences in two normally distributed variables. In the following situations: -Variables have known but unequal variances -Variables have variances that are unknown but ...
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glmmTMB results in R summary() or Anova()?

I am wondering how to analyze differences between subspecies. I want to see if body mass differs between 3 subspecies of rodent and if sex and reproductive status are also different. We then want to ...
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Compute a quantile of a bimodal distribution composed of two normal distributions with known parameters [duplicate]

I have a bimodal distribution which is an equally weighted mixture of two normal distributions with known means and standard deviations. I can easily compute a two quantile values using the percent ...
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Why pdf is not considered and cdf is considered for estimating probability of a value [duplicate]

I am a learning statistics on my own and I am a beginner. I came to know that to construct a distribution curve one has to first create histogram. Let's assume that it is a normal distribution. Then ...
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1 answer
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Basic question: Determine how significant a deviation is

I'm just getting started with statistics - so far I'm familiar with the basics of descriptive statistics. It's a basic question that has probably been answered a thousand times. However I don't know ...
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1 vote
2 answers
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Suggest me best statistical test

I have data of frequency of 10 males( birds) voice across age. And I want to study how peak frequency ( one of the acoustic parameter in bird's call) of males call changes as they age. Call data taken ...
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Comparing survey multiple choice survey questions response percentages between a subset's responses and the total collected responses

I have a survey composed of multiple choice questions. Several distinct branches of the same organization responded to the survey. I want to see if the distribution of answers from one branch is ...
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1 answer
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A measure of variability/dispersion that captures only one direction of change

I am conducting a study trying to correlate changes in a biologic parameter (e.g., blood bilirubin concentration) with clinical outcomes (e.g., bleeding). I have found that variability in such ...
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2 votes
2 answers
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Models for describing cluster change over time

Suppose I have a set of observations encoded as a matrix $X$ whose entries $X_{it} \in \mathcal{C} $ correspond to cluster labels of experimental unit $i$ with repeated measures at time $t$, where $\...
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Comparing frequency between groups

I'm using SPSS, new to statistics. I have 2 groups of patients (Group 1: 1000 patients; Group 2: 400 patients). One of five different interventions (surgery a,b,c,d,e) was performed on subjects in ...
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