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.

344 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
6
votes
0answers
347 views

T tests on proportions - Wrong, but how wrong?

Background: In psychology, and probably a number of other disciplines, it's common practice to test between-groups effects on a binary variable, such as accuracy, by aggregating data within ...
5
votes
1answer
1k views

2-Sample Proportions z-test vs Fisher's Exact Test

I want to evaluate the difference in proportions in declined applications and exceptions from policy from one quarter of data to the next. My sample sizes are generally not small (several hundred to ...
4
votes
0answers
127 views

Statistical significance of a difference between poll percentages with a small sample?

Analyzing my company’s internal survey results, I was stuck with calculating statistical difference between percentages. I usually used a Z-test as described below, but I am not sure whether it is ...
4
votes
0answers
2k views

Two-Sample Hypothesis Test for Difference Between Two Proportions: Pooled vs Unpooled? How to Choose?

When are you supposed to use the pooled formula vs the unpooled formula? My understanding is that you use the pooled formula when testing a hypothesis where the null hypothesis is $H_0 = 0$ and the ...
4
votes
0answers
90 views

Testing differences between slopes by examining proportions rather than interactions

In a recent article published in Nature Genetics, Francioli et al. argue that the relationship between paternal age and mutation rate depends on what part of the genome you're looking at (intergenic ...
3
votes
0answers
24 views

Statistical Test for Evolution of a Population Proportion?

The problem I am faced with is as follows - there is some population proportion $p$ of people with a certain characteristic that is evolving over time. We take new samples every day (without ...
3
votes
0answers
109 views

Calculating a Confidence Interval for a Proportion for a Sample of Different Size

I'm interested in a (preferably analytic) solution or approximation to the following problem: Let $s_1$ be a sample from an unknown distribution of size $N_1$ and with proportion of successes $p_1$. ...
3
votes
0answers
149 views

Why don't we use the n-1 correction for standard error of sample proportion?

From my understanding, when we construct a confidence interval for a sample mean with a sample size of n, we try to estimate the standard deviation of the sampling distribution $$σ_{\overline{x}} = \...
3
votes
0answers
85 views

Confidence interval of proportion of a proportion

Let's say we have $N$ users. Some of them could be hackers and some not. Only for a random $p_u$ percent (e.g. 1%) of users have we actually investigated manually to know which ones are hackers and ...
3
votes
0answers
72 views

Confidence Interval for a proportion, with false negatives/positives

I have a fairly simple problem but haven't been able to find any resources with the solution. Let's say we have a population of N subjects. We get a sample of size n, and within that sample we have k ...
3
votes
0answers
102 views

why use an odds ratio instead of a proportion

I would appreciate your advice regarding a 'work' query, in that nobody at work can agree on what appears to be a very simple statistical analysis. I have changed some of the details to protect ...
3
votes
0answers
61 views

Is 5 in 100,000 the same as 50 in 1000,000 from a Bayesian perspective?

I am learning about bayesian reasoning and I was having a discussion with a friend about it. My friend asked me this question, which I couldn't answer (this is not a homework, I am an adult learning ...
3
votes
0answers
2k views

Understanding output of prop.test in R

Specifically, I wish to understand the meaning of the confidence interval. An example: ...
3
votes
0answers
808 views

Using chi-squared or Fisher's exact with replicates

I want to compare proportion data (sex ratio) between two treatments. There are 19 populations for each treatment (i.e., 19 replicates). The specifics of the data is that it is the proportion of ...
3
votes
0answers
96 views

Multiple binary responses per participant in a 3 x 2 factorial ANOVA

As part of my thesis in linguistics, I'm currently analysing whether emotions influence the use of adjectives in speech. In my experiment, each participant (N = 90) produced multiple independent ...
3
votes
0answers
55 views

How can I account for range restriction when meta-analytically aggregating differences based upon bounded measures such as mean proportions?

Background and Problem In the past, I have read or conducted meta-analyses that aggregate effects based upon mean proportions. For example, in a typical psychological experiment dealing with human ...
3
votes
0answers
265 views

test statistic for change in proportion over time?

Stats novice here. This is my problem: I have 7 samples corresponding to the years 2006-2012, representing emergency department [ED] visits. For each ED visit, X=1 if the visit had diagnostic ...
3
votes
0answers
625 views

Testing the difference between multiple paired proportions with different sample sizes

Is there a hypothesis test similar to the paired t-test for testing if the difference between a number of paired proportion estimates is significantly different from zero? The data consists of 2 lists ...
3
votes
0answers
183 views

Appropriate test (in R) for proportion data that aren't normally distributed, aren't based on counts, and include 0's and 1's?

I'm studying differences in tree health among 5 species of trees across 3 different green infrastructure types. Here are the first few lines of data: ...
3
votes
0answers
172 views

Can I use OLS with robust standard errors to analyze proportions?

I have a response variable that is a proportion. It is not the outcome of a series of Bernoulli trials, so there is no numerator/denominator, just the proportion. I'd like to assess the relationship ...
3
votes
1answer
164 views

How to Compare more than two Averages of Proportions or Means of Proportions

My experiment deals with $60$ subjects, one third of them belong to type A subjects, $i=1..20$, another third to type B, $i=21…40$ and finally type C, $i=41..60$. Each of these $60$ subjects from the ...
3
votes
0answers
701 views

Appropriate GLM when response variable is proportion, but not binomial

The response variable I'm dealing with is the proportion of a total area that is suitable habitat for a species of interest. So although the response variable is bounded between 0 and 1, my intuition ...
3
votes
0answers
114 views

Generalization of Chernoff bound to Bernoulli schemes

I have this (I think) simple problem, which I guess is just a generalization of the Chernoff bound to Bernoulli schemes. Assume I have a bowl with N balls with R different colors. The balls are not ...
3
votes
0answers
203 views

Appropriate statistics for proportions where categories are composites of independent binary variables?

I have data in the form of three digit binary numbers (i.e. 100, 101, etc.) scored for each individual in my samples taken from two populations I wish to compare. The three numbers represent ...
3
votes
0answers
11k views

How can I calculate the standard error of a proportion?

I made a comparison of hatch success between 2 populations of birds using R's prop.test() function: ...
2
votes
0answers
20 views

Proportion Test on Proportion Data

I'm attempting to analyze the results of a game where one player is eliminated each round. I want to try to evaluate whether a player who wins an advantage in the first round of the game (usually one ...
2
votes
0answers
31 views

Hypothesis test involving proportion of proportions

I have 100 different coins, each with probability $p_i$ of being heads - but these $p_i$s are unknown. I flip each coin $n_i$ times, and see that it lands on heads $x_i$ times. So the proportion of ...
2
votes
0answers
11 views

Which statistical test for two group proportions over two time periods? 100% sampling, capped membership. Independent groups over time

I'm comparing the number of male and female hires at a city in the 1980's to the number of male and female hires in the 1990's. I'm looking for whether the percentage of females increased ...
2
votes
0answers
35 views

I have a proportion DV with true 0 and 1. Which mixed modelling approach (in R) is most recommend?ed?

Hope this isn't too much of a dumb question. I've been searching for a definitive answer, and now I've got choice paralysis. I have a proportional DV (accuracy) with true 0 and 1 values averaged for ...
2
votes
0answers
23 views

Regression alternatives for proportional data that do not rely on the 0 - 1 interval

I'm currently analyzing data consisting of change in cognitive performance and how it is related with a physiological variable (enzymatic activity) in a group of people. As all people were assessed ...
2
votes
0answers
35 views

Measure for variability of proportional data

I have a list of expected values (E) for the proportions of 20 amino acids in protein sequences.In a particular set of protein sequences these proportions differ from the expected values. In a subset ...
2
votes
0answers
29 views

Comparisons of multiple related proportions

Here's the setup. I am testing the sensitivity of my method compared to a baseline method. I have tested this at a number of sample sizes, and I'm recording the proportion of rejections I get in 1000 ...
2
votes
0answers
100 views

What to do when predictors are proportions that sum up to one?

I have a situation as the one described in the links below: Interpreting proportions that sum to one as independent variables in linear regression Predictor variables sum up to 1 but not necessarily ...
2
votes
0answers
242 views

When to use Chi-squared and when Z test for categorical variables?

The problem is: There was a survey conducted among 1137 adults from California, Nevada, and Oregon. They were chosen randomly and they answered to the following question “Do you think Marijuana ...
2
votes
0answers
46 views

Chi squared test: which is the correct null hypothesis?

I'm reviewing some literature in my field, specifically looking at whether physical activity (PA) has any beneficial effects on cognitive performance. The results across the studies are quite mixed. ...
2
votes
0answers
86 views

Beta regression where fractional response adds up to 100%?

I have a data set of people switching brands. Say #people switching from Brand A to Brand B, C or D. My data looks like this ...
2
votes
0answers
460 views

z-test of proportions vs chi-squared

A 2-sample z-test of proportions and a chi-squared test can both be used to analyze a $2\times 2$ contingency table. In fact, for $2\times 2$, $\chi^2=z^2$. Why can the same table, being used with two ...
2
votes
0answers
31 views

What are the chances of seeing a photo 2 days in a row?

I've installed a photo slideshow on a small TV in our kitchen, which displays a randomly chosen family picture amongst 3'700, once every 20 seconds. My wife frequently observes "but I saw that one ...
2
votes
0answers
433 views

Test difference of population proportion and weighted sample proportion

I want to test for differences of the known proportion of the population vs. the proportion of a sample. The sample is weighted by sampling weights. The sum of weights is equal to the size of the ...
2
votes
0answers
95 views

How to compare the marginal variation of two groups with a big difference frequency between them?

I have two different groups (A) and (B) and I would like to compare the marginal variation of the frequency for each time of both groups but, each one of them has a different frequency for a given ...
2
votes
0answers
28 views

Can I use a Chi Squared test if one participant contributes more than once to the same cell

I have an experiment that can be thought of in this manner: I have two rooms and in each room I have two buttons: one red and one blue. One of the rooms is painted blue and the other is painted red. ...
2
votes
0answers
193 views

Aggregated Count Data-Days in the last 30- Negative Binomial vs Beta Binomial vs Binomial Regression

I need help choosing between the binomial, negative binomial, and beta-binomial distributions and understanding the rationale of why I would choose one over the other, as well as understanding how it ...
2
votes
0answers
422 views

Compare pairs of proportions for three groups

I have a interesting problem, where patients are categorized in three groups, namely Severe, Moderate, and ...
2
votes
0answers
52 views

What should the estimated proportion be for the population when the sample proportion is 1?

I am auditing insurance claims for fraud. In my random sample, all the claims are fraudulent. Could I say for the population that the estimated proportion of fraud is 1? I know how to compute a ...
2
votes
0answers
131 views

Is this an appropriate use of a GLM? and if so how do I predict a specific outcome?

I am hoping that someone might be able to provide me with some assistance. A colleague of mine was told to use a GLM of family binomial and a logit link function for some of the data they submitted in ...
2
votes
0answers
320 views

Compare two dependent variables of proportions

I have a group of 20 subjects that is measured twice (pre- and post-treatment). Each time the measurements are proportions. Values range between 10% and 40%. Both variables are not normally ...
2
votes
0answers
64 views

Paired or unpaired median proportion?

I have measured the presence of a disease (present/absent) in pupils at 10 different schools. Then, disease severity was determined as mild, moderate and severe in those pupils with the disease (the ...
2
votes
0answers
63 views

How to test whether multiple independent proportions are different from a given value?

I have a dataset of count data: the number of times a behaviour was performed by either of two individuals in a chamber (a focal individual and a partner), with multiple independent tests across ...
2
votes
0answers
279 views

Logistic regression to predict the fraction of small fish among all fish

My question is regarding to which logistic regression test fits my goal best. My data set contains 641 rows of which each row is one sample with several independent variables (continuous, nominal and ...
2
votes
0answers
1k views

Comparing percentages with unequal sample size

I am comparing the percentage of 5 areas with regards to the magnitude of poverty, income distribution, proportion of women etc. Two of the five areas are independent cities and the three other are ...

1
2 3 4 5
7