Questions tagged [median]

The median is the value below which half the data or probability distribution lies - when the sample size is odd, the median is the 'middle' value of an ordered sample.

Filter by
Sorted by
Tagged with
1
vote
2answers
25 views

How generate random data that satisfy specific constraints such as having specific median? in R [closed]

In general, how can I simulate data that exactly satisfies a set of constraints? I'm in need of generating a set of random numbers, which conform to a given median (not mean), and also fall within ...
4
votes
0answers
42 views

Approximating the median of a $\Gamma(\alpha,1)$ distribution with $0<\alpha<1$

Is there a good approximation (or useful bounds) for the median $\nu_\alpha$ of a $\Gamma(\alpha,1)$ distribution with $0<\alpha<1$? I have only been able to find things like Berg & ...
1
vote
1answer
24 views

Statistical test for preference data through average differences or is other method more suitable?

I need your help. I'm designing a questionary and there I want test which version the people prefere. Which of the following methods is better and which statistical test for significance in each ...
0
votes
2answers
41 views

Best measure of central of tendency

I just started learning stats a few weeks ago well my question is that as we know that the mean, median, and mode is the central tendency of the data and its suggested that we shouldn't go with only ...
0
votes
0answers
18 views

Interpretation of boxplot overlaps

Let's assume that I have the boxplot below that shows fraction of hits for a query. I'm trying to understand if there are any meaningful differences for each type (x,y) and for each category (A-D). ...
1
vote
0answers
34 views

Dividing data by median of the data

I am reading a paper[1] and the authors wrote: "Finally, each column was divided by the median value of the corresponding column to remove systemic deviation" My question is: How does doing this ...
1
vote
1answer
29 views

Existence of a Smoothed Median Function

The median of a finite set of data depends on the data in a continuous, but non-smooth way; this can be demonstrated by considering the median of the data set $\{ 0, 1, x \}$ as $x$ varies. I wanted ...
1
vote
2answers
73 views

How to calculate the probability that the median exceeds a certain value?

Given the pdf $f(x)=\begin{cases}2x&\text{0<x<1}\\0 & \text{otherwise}\end{cases}$. What is the probability that the sample median based on a random sample of size 3 drawn from the ...
0
votes
2answers
22 views

Checking of Measurement in Grouped Data

My teacher uses the formula below when looking for the median and mode of a grouped data. $$ median = L_m + c\frac{\frac{n}{2} - F_{m-1}}{f_m} \\ mode = L_m +c\frac{f_m - f_{m-1}}{2f_m-f_{m-1}-f_{m+1}...
1
vote
0answers
31 views

Using a permutation test to test for differences in the median between two groups when distributions of the variable of interest are not equal

in the following, I will define (1) the hypothesis I wanted to test, (2) the method I used, and (3) the problems that I feel are present. My dataset consists of measures of one dependent variable for ...
2
votes
1answer
47 views

ANOVA for median and interquartile range

I have 5 samples of different sizes (5000-15000 observations each) from 5 (presumably different) distributions. I need to perform something like ANOVA to test the hypothesis that these distributions ...
0
votes
0answers
10 views

Is it possible to derive the median of a distribution from the mean and Gini Index?

I have some data on GDP, population, and the Gini index for various countries, and I would like to derive some median metric. To put it more broadly, given the sum $\sum_{i=1}^{n} x_i$ and size $n$ ...
0
votes
0answers
24 views

Choosing the best aggregation location measure

I'm trying to analyze a granular dataset that is composed as follows: ...
0
votes
0answers
42 views

If Mann-Whitney U is a median test? Then what the heck is “unpaired pairwise median”?

Header: I am really sorry for the confusing title. I am going to edit it so it fits the responses I get based on Mann Whitney U. So I had this exact question on stack overflow about is the Mann ...
1
vote
2answers
163 views

When does the sum of the medians = the median of the sum

I have two random variables (say x1 and x2) defined by empirical probability distributions, and would like to calculate the median of their sum. Under what circumstances (in terms of the ...
1
vote
2answers
195 views

What is a reasonable sample size for median statistics?

I am asking this question because of a recent question on Skeptics.SE and a 2015 study by Duke University and the Federal Reserve Bank of Boston. This question is based on the study. In a Boston ...
0
votes
0answers
19 views

Random Forest Underperforms Median on Training Set for Toy Regression Problem

I have found that random forests is failing on a toy regression problem. My prior impression of random forests is that it is very robust, so I expected that, on the training set, it should always ...
1
vote
0answers
24 views

What types of analysis will work on a dataset of medians?

The dataset I currently have is wages for different occupations across different geographical regions, however each observation is a median. For example, a doctor in region A, the wage reported would ...
0
votes
0answers
18 views

When is variance a better description of spread over IQR? What about mean over median for description of center?

I was reading that IQR and median are a better representation of spread and center when there are outliers and when the distribution is skewed. When is variance a better measure of spread? What about ...
1
vote
3answers
112 views

What's the best method to measure relative variability for non normal data?

I have a set of data that states the volume required each month for the next 12 for 750 raw materials. I would like to determine the variability in the demand for each material, and categorise the ...
0
votes
0answers
28 views

calculate the average visits and running days

What do I've got? I have received a huge data from a real estate portal. It contains more than 50 million rows and data for over 10 years. In addition to the rental prices and other parameters (...
0
votes
0answers
34 views

Median for symmetric distribution

When do the spatial median or the L1-median and the componentwise median coincide ? Does it happen for only a symmetric distribution or other cases too ? Also, are both of them equal to the mean for a ...
1
vote
0answers
51 views

Bootstrapping a sample of discrete data

I am using the bootstrap to calculate 95% confidence intervals for the median of a population. The data can only take positive integer values. My sample indicates a fair bit of variability, though ...
0
votes
0answers
26 views

Am I allowed to create a cumulative frequency distribution from non-normally distributed data?

I have data gathered from a circadian rhythm experiment and I like to present this data as a percentile cumulative frequency distribution (CFD%), because I think this is a clean way to present the ...
1
vote
1answer
82 views

Should I compare the median or mean for my data?

I have a data frame in R that contains the information about 252 freshman university students. ...
22
votes
4answers
3k views

Why does mean tend be more stable in different samples than median?

Section 1.7.2 of Discovering Statistics Using R by Andy Fields, et all, while listing a virtues of mean vs median, states: ... the mean tends to be stable in different samples. This after ...
0
votes
0answers
19 views

Point estimator and confidence interval for median and mean [duplicate]

I want to find point estimator and confidence interval for both median and mode of number of samples that we've collected from a number of simulations. What I've done so far is that I found a point ...
1
vote
0answers
23 views

Testing differences in 5 star rating (Which hotel to choose)

Say, I want to choose a Hotel with the following ratings (1-5) on TripAdvisor. This seemed interesting if the mean for the Hotel with smaller number of votes is bigger than the mean of the hotel with ...
0
votes
2answers
73 views

Can the Median and mean be “zero”? [closed]

I have a data set with 32 variables. I take the summary of these variables. I found that some of these variables have a Mean or Median equal to zero. Is that Ok? Can I still work with this data set? ...
1
vote
1answer
55 views

Inference using robust statistics

I'm simulating the overall usage of a cluster using historic deployment data. Due to the nature of the simulation, there are some heavy points (i.e. very low overall usage). As a result, the variance ...
0
votes
0answers
10 views

Estimating yearly diagnosis rate from multiple studies

I want to estimate yearly diagnosis rates from some 8 studies. Each of the 8 studies contains the following data: $n$ = total number of patients (e.g., 100) $t_{start}$ = start timestamp of the ...
0
votes
0answers
16 views

Merging categories with small n (or median splits on categorical variables)

I've found a lot of resources on why median splits on continuous variables are generally bad, but I haven't found anything on merging levels from already categorical variables, specifically when some ...
0
votes
1answer
26 views

Confidence in Forecasted Median

Suppose I am measuring the time it takes to complete tasks, and I am looking across a year period, say 2019. At the end of the year, I will report on the median time taken across all tasks. Assume ...
0
votes
0answers
17 views

Median point vs. number of points

I am trying to assign a binary label to a group of 2D points. Essentially I want to know whether or not the group lies mainly within a certain region in 2D space, such as above a line. I've been ...
2
votes
1answer
61 views

Expectation of absolute difference between a random variable with its median [closed]

Given a random variable $x \sim p(x)$. Denote $m$ to be the median of x. What is the expected value of $|x-m|$, i.e we would like to compute the following integral: $$\int |x-m| p(x)dx $$
0
votes
0answers
53 views

Wilcoxon signed rank test - interpretation

I have 6 dependent variables that were measured on a 5 point Likert scale (treated as interval here). I want to test if their means differ significantly from the midpoint 3. As the normality ...
3
votes
1answer
61 views

Is my interpretation for Wilcoxon Signed Rank test correct?

I ran a wilcoxon signed rank test on paired samples where the outcome variable was a test score. The samples were paired by as siblings (younger and older sibling). I have a problem interpreting the ...
1
vote
1answer
51 views

Can you compare the mean of one data set with the median of another?

I’m having an argument with another numerically literate person. We both saw a news site state that under no circumstances should you compare the median of one set with the mean of another. It’s ...
0
votes
1answer
75 views

Pseudo median from Wilcoxon signed rank test larger than sample median?

I am left wondering, why I can be in a situation where the pseudo median (population estimator) of a Wilcoxon signed rank test, can be larger than the simple differences between sample medians? I am ...
1
vote
0answers
17 views

Wilcoxon rank signed test, paired or non-paired test?

I have been trying to figure out, whether or not I should use a paired or a non-paired test. My question comes from the fact, that I am trying to get the pseudo median, in order to say that SBP is [x] ...
0
votes
0answers
57 views

Random Forest Regression: More trees are not necessarily better

This doesn't answer my question, and neither does this. Problem I've been experimenting with random forests. I have 30 or so input features and one very right-skewed response. I've noticed that ...
2
votes
2answers
110 views

Wilcoxon signed rank test, getting a numerical media difference instead of p-value?

I have been running the Wilcoxon signed rank test, where my output is a p-value. Now, the p-value interpretation I am confident in, but I read in a paper that the authors reported the: The Wilcoxon ...
2
votes
1answer
47 views

Asymptotic distribution of median estimator when density doesn't exist

We know that when density(say $f$) exists at the median(say $\theta$) then the median estimator(say $\hat{\theta_n}$) has the following property $$ \sqrt n(\hat{\theta_n}-\theta) \to^d N(0,1/\{4f(\...
3
votes
1answer
726 views

Why median is NA for some of the group outcomes in survival analysis?

I'm trying to do survival analysis using the Followup information, patient_vital_status and the expression of gene. I'm using like below: ...
0
votes
0answers
13 views

Real (not rounded) Lower and Upper limits of groups of frequency distribution and Median for infinitely continuous data

From here on page 5: https://www.pbarrett.net/techpapers/percentiles.pdf So how can both be correct – yet seem to be more appropriate under different conditions? The clue is spread throughout the ...
0
votes
0answers
14 views

With few respondents on a 1 to 10 scale, is it better to use a weighted mean or the median?

I have survey data where ~20 respondents replied to some questions on a scale of 1 to 10. For the most part, none of the distributions are Gaussian. A set of questions look to find out a participants ...
0
votes
0answers
21 views

Are median values numeric or ordinal?

I'm trying to set up the input data that I'd feed into my DL model and for the simplicity, I'm thinking of plugging in only the min/max/average values of the original data. (This is necessary for my ...
7
votes
2answers
1k views

Calculate variance without calculating the mean

Can we calculate the variance without using the mean as the 'base' point?
0
votes
0answers
20 views

Paired Wilcoxon signed rank test-compare median

I have been comparing driving behavior before and after a technological intervention for a specific group of people. My data is far from normal hence I have used paired Wilcoxon signed rank test. If ...
0
votes
0answers
11 views

Median of demeaned variables and fixed effects

I have observations of the profit $y_{it}$ for several firms, noted $i$, over time $t$. For each firm, I compute the mean of $y$ over the years and call it: $\bar{y_i}$. Then I substract this firm-...