proportions

1. Proportion Z-score calculator

Hi! I have a sample (of 30) who’s outcome was measured binomially as either YES/NO. The expected population should have entirely NO answers. I therefore want to calculate if there is a significant difference in the proportions between sample of 23/30 (23-YES, 7-NO) and the expected proportion of...
2. Statistically significant changes in proportions - comparing 3 populations

I have data from three populations, 2 observations each populations (opinion poll data from different countries). I am trying to find out if any changes in opinion on the issue i am investigating are statistically significant. So, for one topic In 2010, Group 1 answered 20% yes, Group 2...
3. Determining the probability of a condition occurring

I am looking to determine a sound procedure for the analysis of some data to determine what is most likely to occur given sample plot data amongst a population. I am unsure as to whether what I am trying to accomplish is probability or just frequency distribution manipulation. I am looking for...
4. t-test or z-test for two proportions?

We did an intervention to reduce the frequency of use of a certain type of treatment and now I want to compare the data pre vs post intervention. For each month I have the number of treatments per 1000 patient visits (because the monthly number of visits fluctuates). I have 6 months of...
5. Statistical test for proportions (values' range: 0-1)

I am trying to compare mass spec data from 3 different conditions. For each protein I detected in my samples I have 3 values/condition (from 3 different experiments; see attachment). So, I want to compared these values, that are proportions that range from 0 to 1 (both included), and see if the...
6. Proper analysis for group differences in proportion scores

Hello all, I am running analyses looking at group differences in the proportion of time kids were distressed in a task. I have a task that has been broken up in to 10s time slices and kids receive a score of 1 in each slice they evince distress. To create my outcome variable, I am dividing...
7. Fisher's Exact test and subjects with multiple observations?

Hi Everyone, I was wondering if I could please have some advice on how to deal with data that have multiple observations for some of the subjects (but not all). We are looking at list of 150 patients who are currently receiving therapy for various illnesses/indications. We are planning to...
8. CLT and Proportions

I would like to ask those of you who know their CLTs and Proportions a few questions. I am completing my HW right now and wanted do ask you guys a few Qs please. :wave: Example: The mean price of shoes in a certain store is $585 with a standard deviation of$195. I am randomly selecting 35...
9. Fisher's exact test - 2x1 versus 2x2 contingency table

Hello everyone, I am having a problem comparing proportions between groups. My problem: A mouse can enter door A or B. I have two groups. In group 1, 90% of mice enter door A, in group 2, 55% of mice enter door A. I want to test whether there is a difference in the proportions of entering...
10. Comparing proportions

Hello, I need some help knowing what stats to run for my data analysis. I have samples of muscle collected during different seasons and I am analyzing the different types of a specific protein present in the muscle. I want to compare across the different seasons to see if there is a...
11. How to Analyze: Comparing two proportions

Hello, I need advice on how to analyze a simple set of data. For simplicity's sake I'll make up the variables. Question: A store keeps track of the proportion of males vs. females that visit its store every day. On Saturday, the proportion of men and women visiting is 0.5 and 0.5. On...
12. How to analyze proportions from large datasets

Hello all! This question will likely reveal my lack of basic statistics knowledge, but I can't seem to find the answer in textbooks or on this forum. To wit: My grad project involves cutting fragments from leaves, and growing fungi out of them. Anywhere from 15% to 90% of fragments produce...
13. General Linear Model using proportions as raw data - transformation needed?

Hi, I have become confused in my reading of analysis of proportions. I was all set to analyse my data using a general linear model after transforming the proportions using an arcsine-square root transformation, but now I'm not sure if this is a correct approach and more importantly why/why...
14. Chi Squared test of proportions

Hi there, I am currently coming towards the end of my dissertation, and I am looking for a bit of help with how to test distributions using a chi squared test with the data that I have. I have attached a picture of mocked up data that represent what I am trying to test. The first table is...
15. How to model weighted average ratios in the [0,1] interval

Maarten Buis on this forum provided great insight on how to model percentages in the [0,1] interval (http://www.talkstats.com/showthread.php/52986-Modelling-percentages-in-the-closed-interval-0-1). I now have a similar but somewhat different problem, in that I'd need to model weighted average...
16. Which analysis to use for comparison of species proportions?

I have samples of bee populations from 2011 and 2013. There were 5 different species collected. I need a test that can tell me if there is significant differences between proportions of species between years (ie, did one species start to decline and one species start to become more abundant)...
17. proportion inference analysis

Hi. I have data on 1027 potential donors to a non-profit organization. I want to see if our online ads have impacted their donation rates. The people who sent me the data have a record for each of the 1027. They included a "sample weight" column which indexes the demographics columns. So...
18. Comparing proportions from the (somewhat) same sample

Hi everybody, I’m looking for some help on testing whether there are statistical differences between proportions when the data is dependent. By dependent, I mean that all the data is from the same participants though I’m not talking about a repeated measures experimental design but instead...
19. Z Test of Two Proportions with Small Populations

This seems like a fairly basic question but is one that I'm having difficulty answering. For comparing two proportions to test for significant differences, I normally use a standard two-proportion Z test. However, I am working on a project that is a special case: we are surveying a very...
20. Model checking and generalized multilinear regression

Dear all, In my research I am analyzing the quality of game player softwares by making them play multiple times against a certain opponent and counting the number of victories. It seems to be very clear that the random variable of #victories should be modeled by a binomial distribution (as...