Questions tagged [percentage]
Number or ratio expressed as a portion of 100
404
questions
170
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4
answers
205k
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Percentile vs quantile vs quartile
What is the difference between the three terms below?
percentile
quantile
quartile
41
votes
10
answers
10k
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Why is 600 out of 1000 more convincing than 6 out of 10?
Look at this excerpt from "The study skills handbook", Palgrave, 2012, by Stella Cottrell, page 155:
Percentages Notice when percentages are given.
Suppose, instead, the statement above read:
...
23
votes
4
answers
11k
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Is 50% 100% higher than 25% or is it 25% higher than 25%?
If I have two values A and B which are both expressed as a percentage of C, and I want to express the difference in magnitude between A and B as a percentage D, is it more correct to express D as a ...
21
votes
4
answers
67k
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Using ANOVA on percentages?
I have a table with four groups (4 BMI groups) as the independent variable (factor). I have a dependent variable that is "percent mother smoking in pregnancy".
Is it permissible to use ANOVA for ...
20
votes
7
answers
4k
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What kind of curve (or model) should I fit to my percentage data?
I am trying to create a figure which shows the relationship between viral copies and genome coverage (GCC). This is what my data looks like:
At first, I just plotted a linear regression but my ...
18
votes
3
answers
30k
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What are the issues with using percentage outcome in linear regression?
I have a study where many outcomes are represented like percentages and I'm using multiple linear regressions to asses the effect of some categorical variables on these outcomes.
I was wondering, ...
12
votes
6
answers
2k
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Example distribution where 74% of probability is above the mean
Watching Why You Should Want Driverless Cars On Roads Now, at 8:14 Derek Muller claims:
Surveys show 74 % of people believe they are above average drivers.
This claim motivates my question, but some ...
10
votes
4
answers
2k
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How to compare -50% and +100%
This might seem (and be) a really trivial question!
I have this table:
...
10
votes
1
answer
9k
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Mixture of beta distributions: full example
I have a vector of measured proportions and want to
test if these proportions follow a bimodal distribution
characterize the two underlying distributions
determine for each data point which ...
9
votes
1
answer
6k
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How can percents not adding up to a hundred be possible?
I was reading this paper about aquaponics and some of the stats did not make any sense with regard to the percents listed. What method would allow these percents to exist?
The most commonly raised ...
9
votes
1
answer
6k
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Why can I interpret a log transformed dependent variable in terms of percent change in linear regression?
Looking at resources such as this one and this one, you see claims like
"Exponentiate the coefficient, subtract one from this number, and
multiply by 100. This gives the percent increase (or ...
9
votes
2
answers
8k
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Is it correct to model percent change as a continuous variable?
I have data from a longitudinal study where there are 46 subjects, each with 13 observations over time on a given outcome measure. A prior analysis conducted on this data performed a linear mixed ...
8
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4
answers
3k
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Dungeons & Dragons Attack hit probability success percentage
In D&D players roll a 20 sided die trying to beat a set number to determine if an attack hits the target. Players often can add modifiers to this roll to help the odds in reaching this target ...
8
votes
1
answer
2k
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Can a standard deviation of raw scores be reported as a standard deviation of percentages?
Suppose we have a test consisting of 30 questions, and 10 people take this test. The mean test score of these 10 people is 17, and the standard deviation of all the scores in the sample is 4. When ...
7
votes
2
answers
5k
views
Is correlation a percentage?
The Pearson correlation coefficient ranges from -1 to 1. Oftentimes, people take this number, multiply it by 100 and call it
-17.3% correlation
or
63% correlation
I was once dinged by reviewers ...
7
votes
1
answer
281
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How many tests should we do to estimate the percentage of people who contracted COVID-19 in Lombardy?
Lombardy, a region of Italy, registered many severe cases of COVID-19 in the last few months.
Unfortunately the available data don't allow us to estimate the percentage ...
7
votes
5
answers
15k
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How to convert sport odds into percentage?
I am wondering how to convert sport odds to the percentage format.
There's this example:
...
7
votes
2
answers
13k
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What regression model to use when independent variables are percentages to predict % outcome?
"Independent" variables: time spent (% at work, % sleeping, % exercising), body mass composition (% fat, % muscle, % bone)
Dependent variable: Smoker (1) or Non-Smoker (0)
What kind of regression ...
7
votes
3
answers
46k
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Is it incorrect to calculate the mean and standard deviation of percentages?
My data is some percentages on how many transactions from a whole are missed each month. The percentages are for 13 months and ranging from 97 to 99 percent. I was asked to calculate the mean and ...
6
votes
1
answer
474
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Deal with percentage data
For instance, I have such data:
...
6
votes
1
answer
899
views
How do I test difference in Percentages?
I have some survey data and know the number and percentage of "yes" responses. How do I determine if any of the percentage yes regional responses are statistically different from the national yes ...
5
votes
4
answers
49k
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Should percentages be reported with decimal places?
When presenting data using a percentage, is it a good thing to have decimal places, say 2 decimal places instead of rounding off to whole numbers?
For example, instead of 23.43%, you round off to 23%....
5
votes
2
answers
4k
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How to interpret a regression coefficient of an independent variable expressed as a percentage?
I fitted a continuous dependent variable against two explanatory variables. However, one of the explanatory variables is expressed as a percentage. Consider the regression model: $y = 0.05 + 0.032x_1 +...
5
votes
3
answers
793
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Adjusting round-off error so as to have percentages that sum up to $100$
I have non-negative numbers $x_1, \dots, x_n$. These numbers are all percentages rounded to the nearest tenth of a percentage. Unfortunately, I don't have any of the numerators or denominators driving ...
5
votes
1
answer
211
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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 ...
5
votes
1
answer
377
views
Shift the mean of a (not) normal distribution but keep same scale
Warning: I am not a statistician, so please go easy!
I have a (not) normally distributed measure of a population, with possible values from 0 to 100%. Its mean is 60%.
I need to be able to shift the ...
5
votes
2
answers
17k
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T-test on percentage values (among experimental replicate values)
My experiment involves looking at the precentage of cells in a slide that have a particular property under condition A and condition B. I have one slide for each condition. I have done this experiment ...
5
votes
1
answer
2k
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How to test if a percentage is significantly higher than 0?
I have asked people to rate different items between 0 and 100.
On one condition, most of the items were rated very low. Therefore, the distribution of the result looks like an negative exponential.
...
5
votes
1
answer
5k
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Percentages as the response variable in GLMM (glmer), proportional binomial or not?
After looking through several questions on stackexchange, and even applying many of the suggested methods I have come to a point where I would like to have an expert's advice if the methods applied on ...
5
votes
1
answer
20k
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How to calculate the Standard Deviation of a set of Percentages
I would like to know how to calculate the standard deviation (SD) of a set of percentages. Let me explain better.
Some students performed a test and I counted the number of right answers for each ...
5
votes
0
answers
187
views
Which approach can be used to regress sleep time on brain mass, in this data set?
I was reading this blog post:
https://htmlpreview.github.io/?https://raw.githubusercontent.com/avehtari/BDA_R_demos/master/demos_rstan/sleep.html
the author describes a model to predict how many ...
5
votes
0
answers
744
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Percentile vs Percentile rank
I have the read the definitions many times and I still don't quite understand the difference.
This article says:
A statement such as:
"A score of 600 has a percentile rank of 80"
has a ...
4
votes
2
answers
340
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Win Percentage Question
I have noticed my gambling win percentage (in online pool) is very hard to increase as time goes by. After 1500 games, I'm stuck at 57%. If I want to increase my overall win percentage to 60% after ...
4
votes
1
answer
22k
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Chi Square Analysis Percentages
I've used chi-square analysis in school, but was absent for the lesson, and I never quite got the hang of it. I've been successful with it in the past, but now I'm trying to use percentage values, and ...
4
votes
1
answer
3k
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Power Calculations using "Percent Change" vs. "Absolute Values"
Percent change can be extremely misleading for a number of reasons (e.g. regression to the mean), even though in the medical literature percent change is used quite frequently to "normalize" clinical ...
4
votes
1
answer
424
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Judging the quality of a statistical model for a percentage
I have a data set with multiple predictors, and a single response variable which is a percentage, thus is bounded between 0 and 100. I cannot share the dataset unfortunately. I would like to build a ...
4
votes
1
answer
1k
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Is it possible to find the 99th percentile using other percentiles?
I have the 10th, 20th, 25th, 30th, 40th, 50th (I assume this is the same as the mean), 60th, 70th, 75th, 80th and 90th percentile values of a data set. This is for the distribution of salaries in the ...
4
votes
2
answers
2k
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How to analyze percent data when most of the data is 0%?
I have a set of percent data on histological abnormalities in fish gills and I need to compare the results between two sites A and B. We analyzed abnormalities in lamellae of a particular gill arch. ...
4
votes
1
answer
9k
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Is taking the median of a set of percentages statistically sound?
I have several sets of data, unfortunately the data comes to me in a "summary" form. My job is to consolidate the several data sources into one general summary. I'm currently using the median to ...
4
votes
1
answer
1k
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Comparing a distribution of percentages
I have two populations that I would like to compare, each of which contains N samples. Each sample itself contains many events that can be categorized into 20 different, mutually exclusive, categories....
4
votes
0
answers
61
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Rank forecasting from uneven samples
Say we have a bag of chocolate balls. There are $I$ different unique colors. Our bag has an unknown number of balls for each color.
We want to get a sense of which color people like the most and ...
4
votes
0
answers
20k
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Comparing two percentages
How would I go about comparing two percentage figures from two different sample sizes? For example:
Sample 1 - 10% (220,510 out of 2,205,100) of respondents answered "yes",
Sample 2 - 31% (12 out ...
4
votes
0
answers
677
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Distribution of percent difference of two normal variables
I have two performance measures in a given experiment that I know to be approximately normally distributed:
$X_1\sim \mathcal{N}\left(\mu_1,\sigma_1^2\right)$
$X_2\sim \mathcal{N}\left(\mu_2,\...
3
votes
2
answers
1k
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Dealing with Heteroscedasticity in ANOVA
I need to perform an ANOVA on percentages data. I have 3 factors: TREATMENT, SAMPLE and DaysAfterTreatment (DAT).
Treatment has 3 levels: Control, A, B.
SAMPLE has 2 levels: SampleA, SampleB.
DAT has ...
3
votes
3
answers
2k
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I know the probability of an event to occur, so how do I find how many times the event must be attempted to get a reasonably chance of success?
If there is a 2% chance of event X to occur, how many times must X be attempted to have a reasonable probability of occurring at least once?
What is the formula used called, and how do I solve this?
3
votes
2
answers
4k
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Normalizing sample sizes to identify trends
Every month I send out an email to prospective customers. The client I use tracks the number of recipients and the percentage of the emails that were opened.
Here's a sample, there's thousands of ...
3
votes
1
answer
1k
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Interpreting odds ratio of an ordinal regression when independent variables are negative percentages
I'm trying to express the results of an ordinal regression with a certain "perspective", and I'm confused.
My dependent variable is an ordinal representing the progression in a scale of negative ...
3
votes
1
answer
1k
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How to properly display changes in percentages over time?
Our company is developing self-learning software that extracts data from documents and enters it automatically into text-fields in some other software, on behalf of the user. These suggestions aren't ...
3
votes
1
answer
900
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Is it possible to statistically test relationships between counts and percentages?
I have counted adult butterfly numbers over 3 areas and would like to compare these counts with the percentage heather cover on each of the 3 areas. Is this possible?
My data looks like this (the ...
3
votes
1
answer
57
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Can I aggregate several continuous variables into percentages and then compare those percentages between groups?
I have a dataset with the concentrations of several lipids. I'm interested in finding lipids that are altered between two conditions, but the lipids are not indepentent from each other and the ...