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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What type of test should be used?

What kind of test would I use to find the answer to this? Is there evidence that cereals promoted in an in-store circular have a higher average number of units sold per store than cereals not ...
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Need clarification on a passage. (Autism Prevalence)

Passage verbatim: According to a review by Silverman et al. (2010), the incidence of autistic disorder is 0.6–1.0 percent in the population. The disorder is four times more common in males ...
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Confidence interval for a proportion

Let's say I want to built a confidence interval for a proportion ($p$). I have seen that many times this is made from the standard error: $p\pm 1.96\times SE(p)$ taking SE from ...
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power of chi squared test for two proportions with gsDesign package in r

I have problem with calculating power for two sided chi squared test for the following design: Study includes 200 patients (100 patients per group). The null hypothesis is that p1=p2=30% and ...
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66 views

Compare differences in dependent frequencies

I would like to compare two error rates (proportion of incorrect answers in questions with dichotomous response-format) for two different items, and I am looking for some advice on how to do that. ...
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10 views

McNemar or chi-square - test for group differences paired and unpaired data

I understand that the difference between a chi-square test of homogeneity and the McNemar test is that the chi square is used for unpaired data and the McNemar is used for paire data. Here's my ...
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44 views

Proportions Test for when one sample has lots of zeros

I tried using chi-squared test, but it is giving me odd results, For example: Let's say that I am testing whether behavior between male and female users is the same. Males only bought 3 units of ...
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21 views

Performing significant difference tests in endline evaluation

we have conducted an endline survey and now comparing the result with baseline survey. I am interested to find significant difference between baseline and endline. One of sample questions is given ...
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42 views

Analysis where dependent variables are proportions

I have a set of demographic data (age, race, social class, etc.) for selected geographic areas. These independent variables are each proportional in each type, i.e. Area A: White 70%, Black 20%, Asian ...
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37 views

Difference between two proportions

How do you compute the difference between two proportions so those differences can be further analyzed? I have some repeated measures data with a first and second data point per subject, and I want to ...
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49 views

Exact two sample proportions binomial test in R (and some strange p-values)

I am trying to solve the following question: Player A won 17 out of 25 games while player B won 8 out of 20 - is there a significant difference between both ratios? The thing to do in R that ...
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Proportion data - beta distribution v. GLM with binomial distribution and logit link

I have a fisheries dataset for which I have calculated value for each grid cell on a map. The value is the proportion of the total fishing sets in that cell for each month/year. So, I have values ...
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65 views

How to compare the proportion female with the proportion male

I would like to know if it is correct to do the following statistical comparison: In a sample of $440$ patients, I have $241$ females ($54.8\%$) and $199$ males ($45.2\%$). Are these proportions ...
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problem: a sample size for the assumed effect in the 2 sample proportion test

I would like to calculate a sample size for the 2 sample proportion test when the significance level is assumed (0.05), power is assumed (0.90) and I'd like 2 sample proportion test to detect that ...
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24 views

How to analyse binary outcome data with between- and within subjects factors?

I am looking for the right statistical procedure to analyse my data (mixed design) with binary outcomes. Between-subjects variable: treatment (yes or no); experimentally manipulated Within-subjects ...
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Proportion (difference) test for drifting proportions

Two machines are spitting out coins (at different non-constant rate). The probability of flipping heads for every machine is believed to change very slowly in time (compared to flipping rate). It is ...
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25 views

Test of proportion vs logistic regression

Basically I have count and proportion data and my explanatory variable is treatment groups (not really but functionally same thing), the information can be summarised in a 2x2 contengency table. I am ...
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modeling a proportion with seasonality removed

I have a time series of proportions that typically fall in the 0.01-0.05 range. I had intended to use GLM to model these proportions, but I ran into trouble when I needed to first remove a strong ...
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Confidence Interval for the average of a set of proportions

If I have a dataset of 500+ observations (people in this case) that has the % of allotted dollars that were spent for each person (so, I have each persons allotted dollars and their dollars spent), ...
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16 views

Population proportion and confidence interval estimation

Q. A disease can be classified into four types. A random sample of size n=100 patients contains $n_1=70$ patients with type 1 disease, $n_2=10$ patients with type 2 disease, $n_3=15$ patients with ...
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13 views

multilevel mediation with a proportion dependent variable sem

I am attempting to test an indirect path in a multilevel dataset with an outcome that is a proportion. The data are a collection of variables related to various qualities of potential support ...
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24 views

Confidence interval for proportions for different patients

Question: Schizophrenia and other psychoses are complex and debilitating diseases, which affect about 2% of the population. Two of the approaches used, as well as in other medical diseases, to reduce ...
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34 views

Questions about non-standard test statistic for difference of two population proportions

Background I'm considering the number of observed 'successes' $x_1$ and $x_2$ from $n_1$ and $n_2$ independent trials respectively. These counts can be considered realisations of random variables ...
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25 views

Confidence intervals of proportions for clustered data

I am trying to compute the proportion of "yes"'s in data that is clustered (participants within cities). If I ignore the cities, I get very nice and narrow confidence intervals. If I compute the ...
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Estimating proportions in a non-nested multilevel Bayesian model

Data: x: 1/0 successes (~ 800 data points) c: city code (1 to 78) t: "time of measurement", 1 (morning), 2 (afternoon), 3 (evening), 4 (night) The problem: I would like to estimate the ...
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Three proportions testing null hypothesis

I have the following question. In a random sample of 250 people with low incomes, 155 are in favour of a new piece of legislation, while in random samples of 200 people with average incomes and 150 ...
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Scaling Specificity to larger data set

Suppose I have the following 2x2 table ...
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probability of sample proportion

I am trying to find the z-score for a sample proportion of 0.39 (The question is actually asking to find the probability of the sample proportion that is greater than .39). The only information ...
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Measurements from two raters. Should I use multilevel/“random-effects” model?

I have several variables that were measured on patients, for most patients the variables of interest were measured by 2 independent "raters". Most of the variables are binary. I need to compute the ...
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Rate of change of sub-population relative to that of the whole population.

I have data for the population size of a community, every five years for the last sixty years. The size of the population fluctuates, but generally increases over time. I suspect however that the ...
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74 views

Hypothesis testing: difference between proportions

I am investigating staff inequality between genders and ethnicities in an institution. I have data on contract types (permanent or fixed term) and pay grades for almost all employees. I want to test ...
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20 views

Expected survival time: comparisons when measurements are an average over other measurements?

Set up We have a few types of interventions. For each intervention, a failure occurs randomly at some time $t$ after start for each subject. We take $n$ measurements of $t$ using $n$ subjects, and ...
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1answer
19 views

Zero-heavy dataset with proportional independant variable

I am examining the effect of a binary variable (rural vs urban) on my dependant variable (total mileage expense). Essentially, a person (n) will do X amount of trips in one year, and Y trips will be ...
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48 views

Pitfalls of using random forest/GBM on proportion data?

I have a set of data with a dependent variable which represents a proportion, and many of the samples contain a response of 1. I would like to build a random forest or GBM regression model on the ...
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two samples, hypothesis test of proportions t or z test

I have two samples of documents where one sample contains documents of a certain category and another sample contains documents of another category. I am analysing the occurrence of a certain word in ...
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29 views

Compare proportions more than two groups

I have a survey where teachers are responding "yes" or "no" to lists of activities that they did in their classroom. There are separate checklists related to separate parts of the curriculum (e.g., ...
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82 views

Confidence interval for the ratio of two related proportions (glass ceiling index)

I would like to compute the confidence interval of the glass ceiling index (GCI), which aims to measure gender inequality in Academia. According to "She Figures", the GCI is defined as follow: The ...
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46 views

When to report proportions and when to report median + IQR for ordinal variable

A colleague brought to my attention documentation for a standardised questionnaire which recommended using the median and interquartile range to describe summary variables created by combining ...
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How to compare series of foreclosure rates wrt to time and place

I have three categories of foreclosure rates in NYC (rates are number of foreclosures per 1000 homes). The three categories are: overall rates of foreclosure, rates for homes within a flood zone, and ...
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histograms/ kernel density estimation for proportion data

I am looking at digital advertising data with the following columns: site_id | impressions_count| clicks_count. I am interested in a histogram of the click through rate (clicks/impressions) across ...
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How to analyze data with restricted range proportions

I have a dataset where one variable is a proportion with a restricted range (say 4%). I would like to use this variable to predict a death rate. Running a simple correlation I'm guessing would ...
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Posterior distribution of proportional difference of two binomial variables

Can somebody point me in the right direction for a treatment of the following problem? I imagine this should be a fairly common problem in medical statistics... Given two binomial random variables ...
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How can I do a test for proportions when the data has been collected weekly from the same general population?

So I have a series of proportions taken weekly for 7 weeks. This is a study of which way spiders were facing. So for example, the first week, 20 spiders were facing out, and 10 were facing in. Now I ...
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How to structure data for SPSS (percentages for log-linear analysis)?

I am a bit desperate because I am writing my Msc thesis and I am not sure how to organize my data for an SPSS usage. My research examines the performance of mobile banner campaigns and how the 3 ...
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1answer
53 views

AB testing vs testing the null hypothesis

I'm trying to understand the difference between testing the null hypothesis (i.e. testing that the probability of a "goal" is the same across 2 different populations, similar to prop.test in R) an ...
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proportions at two times with predictor

I wonder if anyone can help me. My data has 3 main variables: proportions at 2 time periods, and an additional predictor. For example: Item Type Y(t) X Y(t+1) 1 .05 ...
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normalizing a proportion of poll results given unequal gender response rates

I took a poll of patients who experienced at least one misdiagnosis. I'd like to analyze the data according to gender but 75% of the responses came from Females and 25% from Males. Example: The data ...
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35 views

Assessing whether differences between datasets are significant

I am unsure which statistical test I should use to test whether two datasets are significantly different. The data looks something like this: ...
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21 views

What is the best way to quantify concordance of two tests?

I have two different medical diagnostic tests, both test the same condition (binary outcome). The condition in question is rather vaguely defined, so they don't always agree. What would be the best ...
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79 views

Which regression analysis should I use for ranked dependent variables and proportional independent variables?

I am analysing the effect of deprivation on breastfeeding and am wondering which type of regression analysis I should use. It is area level data. Deprivation data is available as a score from 0 - ...