# Tagged Questions

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.

15 views

### Methods and Demographics

Specific question: How do statisticians determine the likelihood that such-and-such type of person will commit a crime? What is their methodology? To illustrate what I'm talking about, people will ...
34 views

### McNemar's test vs chi-squared test for before & after data with different people from the same population

I have 2 proportions I want to compare. They are from the same population but at different time periods, in between which there was an intervention. H0: Proportion in Period#1 = Proportion in Period#...
13 views

### Make inference on overall density of duplicate records from a sample

I have a file, typically of several million records, for which I need to make an inference on the percent of duplicates (perhaps testing for whether the rate exceeds a certain percent, or just coming ...
6 views

### How do I find if two categories of ratio data are different in a manner that is statistically significant?

I have 4 categories of data, A, B, C, and D, that are ratios (market share). Each category has different numbers of records (prescriber-level data). Each record is a market share percentage that is ...
27 views

### maximum of a function from proportions using optim() in R

I would like to receive the maximum of a function f(x) where the x are proportions that sum to one. ...
28 views

### Binomial proportion statistics for variable $n$?

Using the standard definition of the sample proportion random variable: We first suppose $X \sim binomial(n, p)$ is the count of "successes" in $n$ trials where each trial has probability $p$ of ...
20 views

### Comparing Subgroups vs Overall Relative Differences across Treatment

I have two very large unpaired control / variant groups, and a dependent variable that is the success/failure of a binomial, with a relatively small effect size between the treatment groups. If I ...
166 views

### Statistical test for one sample proportions

I am carrying out a study into the handedness of racehorses. There are clockwise and anti-clockwise racecourses. I want to test to see if 1) horses are more likely to win if they are left handed on ...
23 views

### Is it possible to perform statistical analysis comparing a percentage from 1 group to a reference group?

I am comparing dog breeds with a specific disease in my study to a population of registered dogs (no disease information known). The population of registered dogs is not a true reference population, ...
32 views

### Testing trend in proportions?

Simple question: I have a sequence of 10 proportions $(p_1,\dots,p_{10})$ (indexed by time), $p_j\in(0,1)$, that seems to have an increasing trend. How can I test this trend?
8 views

### Conflicting intuitions re linear systems in levels vs shares

Suppose I have a set of components that sum to some total value, different in each period. Call the total Y. I have a set of equations, linear in the (sometimes transformed) variables, each ...
36 views

### Binomial glmer with data between 0-1, not count data, not normal proportion

I have a special case of a binomial glmer and I can't figure out how to properly model it. I have a random factor (1|Species) to account for differences in species....
12 views

### Standard error for an estimate of invented statistic

I created a statistic that is the division of two proportions. Now, I wanted to compute the standard error, which I know how to calculate for each proportion: SE = \sqrt{\frac{\hat{p}\times(1-\hat{p}...
15 views

### Non-GLM Models for Fractional Response Variable

I am searching for a machine learning algorithm that I can use to predict customer retention/churn rate. My response variable is a proportion in the range 0 to 1 (0 and 1 inclusive). I am using R. The ...
25 views

### Diagnostic device hypothesis testing for superiority to a fixed value

I am designing a study to demonstrate that a diagnostic medical device is more sensitive than a fixed performance goal of 70%. Currently I am attempting to determine the appropriate sample size. My ...
36 views

### Which proportions are particularly high or low - compare confidence intervals, or logistic regression?

I have a large database of binary decisions (accept or reject), broken down by state of the applicant, so that for each state I can calculate a proportion of positive decisions. e.g. ...
37 views

### Can I use a binomial model with logit link function when dealing with continuous proportions?

I have continuous proportion data (i.e. ranges from 0 to 1). Or it could be percentage too if multiplied by 100. This is the proportion/percentage of overlap in home range between animals, therefore I ...
60 views

### How to test if a sample proportion matches a population proportion, should I use the z-test or the t-test?

For (a), $H_0 = 0.75$ and $H_a \ne 0.75$. For (b), how can I get an answer with a $z$-value? Why can't I use a $t$-value to answer this question? Is the idea: $p \pm Z (p(1-p)/N)^{0.5}$?
15 views

### Proportional data - Which test

I've recently conducted an in class experiment on cockroach behaviour. But I'm stuck on how to analyse the data. We aimed to seek if the cockroaches would spend more time at the edge of our container,...
23 views

### Confidence intervals on weighted proportions

I am conducting a survey that will identify and quantify the extent to which businesses in a certain industry reuse, recycle and dispose of their waste. I am trying to figure out how I would be able ...
36 views

### Proportion Sample Size Estimation? Cluster Sampling

I was asked by someone running a food drive to help with the following problem: Food is being collected in bins, which hold about 1,500 lbs of food each. They are looking to collect about 500-600 ...
16 views

### Interpreting negative regression intercept; proportion response to categorical predictors

probably a simple answer and I'm overthinking or something. I have regression output (Zero and One Beta regression with GAMLSS). I'm analyzing the proportion of time spent demonstrating a certain ...
61 views

### Why is confidence width narrower, when sample proportions are smaller?

I am using a binomial distribution to calculate confidence intervals around a proportion. I noticed that for a fixed sample size, the width between the confidence intervals gets narrower as the ...
27 views

### Difference in differences in proportions statistical test

I am running a case-control interventional study where the dependent variable/ outcome is a proportion. The cases were given an intervention whereas the controls were not and measurements were taken ...
11 views

### Calculating SE for set of proportions with different sample sizes

Okay, so I have a data set where I'm measuring survival rates under different conditions. I have three treatments, control, pH 1, and pH 2. Each one has six replicates, all of which have different ...
54 views

### Understanding default Bayesian posterior probability shape parameters in multi-armed bandit

Multi-Armed Bandit indicates a best "arm" based on a simple test of proportions and Bayesian posterior probability shape parameters, alpha and beta (some implementations may take a different approach, ...
26 views

### GLM model specification in distribution and link function for fractional (percentage) response data

I have some aggregated data. Indep. Dep. N 1.3 78% 23 1.2 67% 20 Note that both the independent and dependent variables are aggregated by ...
14 views

### Survey sample size

I am trying to learn something about survey design and analyisis and I have a doubt about the number of people that should answer a multipurpose survey in order to estimate several proportions. If a ...
49 views

### How to model percentage dependent variable using logistic regression in spss

I have some aggregated data. Indep. Dep. N 1.3 78% 23 1.2 67% 20 Indep var the average score of people in a particular region. Dep. var ...
10 views

### Two different sample sizes, testing accuracy

currently working on my dissertation for my final year project and have come across a problem. I am not a statistician or a mathematician so excuse me if the question is very simple to solve, can't ...
34 views

### Why does my power vary markedly between a z-test (2 proportions) and a chi-squared test?

I have two groups, with 100 people in one group(1) and 80 people in the other group(2). 42% of group 1 love cake. I am wondering what proportion of the 80 group 2 members would need to love cake for ...
31 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 ...
23 views

### Sample size to test small proportion

What sample size $n$ is required to test the following binomial probability in a single sample: $H_0: p \leq p_0$ $H_1: p > p_0$ Is there an exact, robust formula to calculate $n$ in terms of \$\...
27 views

### Testing statistical significance of three percentages with ANOVA?

I want to compare the mortality rates of three groups. Can I use ANOVA? If so, how will I deal with the percentages?
31 views

### 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....
37 views

### Can I estimate the optimal proportions of ingredients in a blend?

I'm trying to find the optimal blend of 4 ingredients, to maximize liking of a beverage. I can write a function for liking such as: Liking is on a scale of 0 - 1 (0% - 100%). I conducted 10 ...
16 views

### GLM on Proportion Response and Categorical Predictor gives strange standard errors

I am looking at the effects of seawater salinity levels on fertilization rates. Salinity levels are set so they are treated as factors. ...
15 views

### Chi post-hoc OR Z cell comparisons: do 2 proportion z-tests indicate most significant factors?

Attached is an example of some data I'm working with. I'm testing the occurrence of a rare behavior, while controlling for both education and the "bin" variable. The observed sample size is 129. This ...
12 views

### Calculate confidence interval of proportion for cluster sample which none of the subject has the outcome of interest

Let say that I have collected response from 100 subjects using cluster sampling, and none of them has the outcome of interests (e.g. having lung cancer). For simple random sample, I can still ...
23 views

### Appropriate Correction for 2 proportion test? --with example--

Below is an example of frequency data between observed and expected proportions. Can I simply run a 2-Proportion z test here? Or, would I be violating assumptions? If I were to run dozens of z tests (...
15 views

### Mixed effect models and data that has floor effects (and is proportions)(sort of)

I've been asked to analyze some data using linear mixed effect models (via lmer in R). However, I'm not sure this is the appropriate approach to the data. I am going to provide some background detail ...
19 views

### Confidence Intervals for population proportion where the sample proportion = 0 [duplicate]

Does the lower bound of a confidence interval for a population proportion where the sample proportion = 0 (and the sample size is finite) contain 0? If I use the score-based method, it seems to me ...
4 views

### Finding proportion of variability from a model?

With proportion of variability explained by each variable in the model, how do we handle a value that is a negative (-) number? thank you!
14 views

### How do I determine proportional variance between 2 sets

How can I determine whether the proportion of variance for each ID between rating is in proportion to the Allotment? for example in this dataset, rating has a range of 25 while the allotment has a ...
84 views

### Fitting a truncated normal distribution between 0 and 1 with a logit link function in R

I am modeling data that are proportions between 0 and 1, with many values of 0 and 1 in the data set. I'd like to model this as a truncated normal between 0-1, using a logit link in ...
27 views

### Regularized Generalized Linear Models with an incidence as response in R

I'm struggling to find a regularized regression model with a percentage as response variable. I've already seen the glmnet package in R and it seems that there is not way to handle a proportion as ...
7 views

### Confidence interval of a proportion [duplicate]

My objective is to estimate the proportion of A and B in a mixture of A+B. I use a classification method (SVM) which provides classical "error" metrics for classification (percentage of good ...
20 views

### Test equality of multiple proportions

Conciser a cross-tab like this (or equivalent just with different number of either classes or folds): ...
45 views

### Dealing with 0 in cell count for Fisher's exact test

Control Cases A 0 2 B 1000 298 I am dealing with 0 in my 2x2 tables, and I was wondering what are some of my options when it comes to ...
10 views

### comparing proportions in multiple age groups

The hypothesis is that with increasing age the occurrence of ovulation is more frequent. I have binary data (ovulation / no ovulation) for four age categories in cats, some of the individuals may show ...