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Questions tagged [proportion]

A proportion is the fraction of some total that is of a particular kind, either (i) as a count of one type of thing out of a total count, or (ii) as a component of a continuous variable.

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Proportion or (adjusted) count variable as regression predictor with varying denominators

I am attempting to run various different regression models for different health outcomes (i.e., ordered logit for self-rated health, Cox models for survival). My predictor variable is quality of care ...
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Accounting for Pre-Period Bias in AB Testing with Logistic Regression

Question Context This is more of a conceptual question although a concrete example is provided for clarity. My company uses AB testing to understand the impact of various email campaigns on customer ...
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Proper way to test proportions of data points output by a model

I have a dataset with a series $1000$ categoric observations. There are around 250 distinct categories, with $20$ distinct categories comprising around $55 \%$ of the dataset, thus most of them repeat ...
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I Need Help!!! I can't understand this statistics homework! [closed]

In an election, suppose that 55% of voters support creating a new fire district. If we poll 163 of these voters at random, the probability distribution for the proportion of the polled voters that ...
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Why report percentages over proportions?

Proportions and percentages, as I understand them, show the same information. So why report one over the other? Or perhaps what I'm really asking is "Under which circumstances would one be preferred ...
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How to transform observations between different binomial distributions?

Context I am an instructor and I am trying to grade on a curve -- but using a more rigorous mathematical approach than other quick ways I've seen so far. (I'm also interested in this purely ...
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Interpretations of Non-Inferiority

I'm having some trouble really groking non-inferiority for risk difference in a two sample binary proportion. Let $p_1$ be the risk of the outcome from the standard of care and let $p_2$ be the risk ...
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Strange sample size calculation method for one proportion using confidence interval

I came across with the following case in a clinical study regarding sample size calculation for proportion using confidence interval: "The expected value of the primary endpoint was set as 3%, and ...
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Visualization and two-group statistical testing in high-dimension binary data

I am planning a biomarker discovery experiment, and the data is expected to take the form of a high-dimensional dataset where each data point is described by 8 binary variables indicating the presence ...
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Why do we use z-score proportions when we can easily calculate the exact proportion?

What's the purpose of z-score proportions when I can easily find the exactly proportion by counting how many measurements there are in range(x,y) and divide by sample size?
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Calculating the standard error of difference in proportions from paired multinomial variables

I have a data set where respondents are placed into one of four categories at two time points. I've worked up an example in R. ...
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Minimum sample size for estimating proportion of finite set of binary values

I have a finite set of data points where the number of data points has a known size $N$. The data points are binary and independent of each other, they are observations where we have either observed a ...
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Account for the number of Bernoulli trials in the response and selected predictors of GLM?

I have sampled animals at a number of sites and time points. Each site is sampled up to 4 times a year and is sampled over multiple years. At each site*time ...
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Binomial Distribution:equivalency between the average and proportion?

Another user and I are having a debate regarding properties of a binomial distribution, most notably the relationship between the proportion and the mean. The central prompt is in quotations: “I ...
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Exact four-sample proportion test for difference-in-differences analysis?

Assume I have a binomial variable. I can test whether the proportion is different from zero, using an exact test. I can test whether the proportions in two samples are different, using an exact test ...
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Condition “Sample size > 30” for infering population proportion or mean [duplicate]

One of the conditions to use statistical inference, when estimating the proportion of a population based on the sample proportion, is that: The data's individual observations have to display ...
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how to infer population proportion from samples from 2 disjoint subgroups?

Suppose that I know that a large population consists of equal numbers of men and women. I sample 1000 men and ask whether they have ever eaten an avocado. Some number M say yes. Then I sample 1000 ...
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Different results meta vs metafor

I'm running a meta-analysis of single proportions. I know this can be done in both meta and metafor but I am getting slightly different results using both the moment I add in smaller studies. Suppose ...
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determining if ordering is random

Here's the question I was asked: look at the ordering of multiple choice answers a, b, c, d in a test of 100 questions and determine if their ordering is random - or uniform - pardon the terminology. ...
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Statistical approach to differences in proportions between groups

I have performed an eye-tracking experiment where two groups of subjects looked at three pictures. Then I calculated how much of the time each subject spent looking on each picture (in %), giving me ...
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Apropriate test for changes in proportion

I have a mixture of 5 viruses (similar amounts for each) as an input pool. I then passage this Input pool mixture in different cell lines reading the output, and want to see if the change in the ...
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Confidence Limit for Inference on Ratios

I need to know how to construct a confidence interval on a Ratio which is the number of Incidents per Vehicle, calculated as shown for a schematic example in the image below. As shown in the image, I ...
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How can I check if nominal and ordinal data is normally distributed (for z-test of proportions)

This section deals with concepts and procedures for testing inferences about proportions that involve the normal distribution. Following a discussion of the concepts related to tests of ...
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what is the issue with using sample count of unique values to estimate population count of unique values?

Let's say I am drawing a random sample of n values from a population with N values, and in the population, U of them are unique. If I observe u unique values in the sample, why can't I use that to ...
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Converting from incidence rates to raw counts using separate datasets?

I wish to estimate the proportion of all breast cancer patients who are white, black, etc. There are many statistics of incidence rates within each race group, e.g. breast cancer incidence within ...
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How do I test whether an intervention is significant when I don't have the counterfactual sample size?

Let's say I want to figure out whether a specific Public Service Announcement (PSA; you can think of it as an advertisement) to ask people to do an action is effective. That is, the independent ...
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Testing for equality in single-response-category proportions in a multinomial sample

Problem: I have a multinomial variable with three response categories. I am asked to test the effect of certain categorical predictors on the proportion of each category. To my understanding, this ...
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Test Of Equal Or Given Proportions on large number of successes and trials

I have 2 binary matrices, in which 1's represent "critical exons" and 0's represent "non-critical exons". Now I want to know how significant is the proportion of critical exons in first matrix than ...
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Multinomial Distribution

I am trying to quantify a belief that the proportions of testing conditions I have subjected my test units to is representative of my population proportions(known). My data is a number of hours spent ...
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33 views

Interval width for truncated confidence intervals

I'm conducting a simulation study to compare different methods of constructing CIs for a single proportion. The traditional (Wald/Asymptotic) CI can estimate the upper and lower bounds above 1 and ...
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Meaningful outcome measure

I'm conducting a research about deaths due to a certain medication. I know the number of deaths, which is rather small (from 4 to 20 a month) compared to the total of times that the drug was used (~8 ...
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Significance test for difference in two proportions over time with independent sampling at each time point?

I'm comparing the same proportion across samples of two different populations taken over time. So, for example, the proportion of 3rd graders with blonde hair, comparing boys and girls, if every year ...
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Statistical test to compare two proportions

I am performing a meta-analysis comparing proportions of patients diagnosed with a disease based on 2 different diagnostic criteria. I have collected and pooled proportions rates (patients with a ...
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34 views

Comparing proportions across three groups, multiple levels

I have three groups. For simplicity's sake, lets say they are "cats", "dogs", and "mice". I have been asked to compare the proportions of each that are "grey", "white", or "brown". So lets say my ...
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Proportional weighting of proportions

I apologize for the horrific title, but I can't accurately express what I want to ask. If I have eight observations with two groups with each observation having a ...
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From the estimator of the population to the estimator of the subpopulation (Proportion)

Say you have a population of size $N$ that can be divided into subpopulations of men and women. The subpopulations are respectively of size $N_1$ and $N_2$ such that $N_1 + N_2 = N$. However, $N_1$ ...
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Fitting a normal CDF using proportion data

I have the following data (prop is like empirical CDF): ...
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How many trials are needed to get a statistically important proportion of 0.003 for a binomial variable?

I want to do an experiment and try to get an initial proportion (e.g., successful rate). The experiment will generate one of two results (either success or failure). I would like to know how many ...
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Confidence interval for population proportion estimate with replacement and known total population

So, I have an experiment that is equivalent to having a bag with $N$ balls of various colors in it, then drawing a ball, marking down its color and returning it to the bag. Repeat this process until I ...
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Incoherent post hoc pairwise Tukey test using beta binomial distribution and betareg()

I am fitting a beta binomial regression to my data, which is proportion data (lifetime reproductive success ratio) ranging [0,1]. I transformed the 0s and 1s following Smithson and Verkuilen 2006 (y.(...
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29 views

comparing proportions of several groups

I have data of existence of a feature in n samples represents m groups. I want to find features with significantly different proportion in a group. I was thinking about the followings, and will be ...
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One sample t-Test for proportional data

I have 4 group of fish (n=28 per group). I have measured the amount of time that a fish in each group spent exploring two different objects (A and B) in a squared shape tank. Then I have calculated ...
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Can I use a t-test on percentage data?

I have fundraising data on two different types of groups, let's call them Group A and Group B. I am looking to perform a hypothesis test on whether organizations in Group A raises more money from ...
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R power.prop.test for two samples with different proportions

I am trying to modify power.prop.test is R to adapt for cases where n1 and n2 (two sample sizes) are not equal. That is, they can not be given by one constant n. The equation in R for n1 = n2 = n ...
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Is chi-square appropriate for this data?

I have data as shown in the picture below where the column, 'school' is the site of the data; 'grp' is indicative of either control(C) or experimental(E); 'tStu' is the number of students. The next ...
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How to test mean differences in proportions that are dependent

I have an experimental setup where I have allowed groups consisting of about 50 animals to select between two environmental conditions. I.e. animals had the possibility to move between the two ...
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Aggregating small area estimates to match a truth

Small area estimation are related group of techniques in the estimation of parameters associated with a sub-population. For example, suppose I have sub-populations $S_1, \cdots, S_n$ with total ...
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Proportions: why changing to population mean estimator doesn't change the distribution

I saw in a few places (e.g. here) when you compare proportions of 2 samples, under a null hypothesis that they are equal, you eventually get to this: $$ \frac{\bar X - \bar Y}{\sqrt{P(1-P)(\frac{1}{n}...
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Hypothesis test practice question

" Prof. J conducts a hypothesis test on whether the proportion of all students who bike to school (denoted as p) equals 30%. Specifically, Prof. J has H0: p=0.3 versus HA: p≠0.3. He obtains a P-value ...
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testing for significance of proportion over time

I'm analyzing a survey over time, last year and this year, and I've been asked to compare the proportion of the two time periods for significance, from the same survey and same question data is ...