comparison

1. Fit review for multiple systems

Hello everyone Im new here so I hope I dont get anything wrong. But heres my question: I am writing my Bacherlors Thesis one chapter of said thesis revolves around finding a better fit to my data than the Van-Deemter equation H(u)=B/u + C*u So after looking through some Data I found about 6...
2. Comparing categories of a independent variable in logistic regression

Hello, I have a doubt about the ways of comparing categories in logistic regression. I have 200 subjects with a dependant variable (positive/negative) and I want to test them with an independent variable (IV) of 4 categories (age). I am going to use a logistic regression, but when I do that, I...
3. Help deciding paired vs unpaired t-test

Hi, I am analyzing an experiment in which protein levels were examined in two different strains of bacteria. Lets call them A and B. Three separate times bacteria A and B were grown up and their protein levels measured. Would each day's samples now be paired since they were grown on the same...
4. Comparison of regression coefficients between (nested) geographic regions

Hi All, I would like to compare the effect of an explanatory variable (say X1) on a response variable (Say Y) between two geographic regions in which one is a sub-region of the other. For example, I am fitting two regression models(Y on X1), one for the city data and the other for country...
5. Comparing means of frenquencies

Hi all, Doing a comparison of keyword search frequencies and need some help determining which test to use to compare means: I was given a list of 200 keywords, and the average number of times they were searched in every month of 2014 and 2015. Took the yearly average for all 200 and want...
6. Sampling issue

I want to be able to make comparisons between a specifically selected sample (based on ethnicity) and a randomnly selected sample from the general population. Even though the specific ethnicity represents no more than 10-15% of the population, my randomnly selected sample from the general...
7. [SAS] Compare predicted vs actual continuous [0,1] data

Hello, I have predicted values for year and quarter that were calculated from a linear regression, and I also have actual values. I would like to compare the actual vs. predicted values to ensure that the model was appropriate. The data are continuous on [0,1]. I had tried a chi-squared...
8. Help needed! Comparison of two datasets

Hi guys, I have two datasets, which basically have data concerning the same event, but recorded by different sources. What I need to do is compare the two data sources. The percentage difference between the two sets fluctuates between 0 and 20%. I'm not sure if percentage difference is the...
9. Interpreting pairwise comparisons for significance when you have 3 groups

Dear posters, I am currently trying to interpret results from three different groups in my study. There is essentially a control group and two picture groups. My original hypothesis would be that one of the picture groups would outperform the other, but post hoc testing revealed something...
10. Comparing variability of several independetly time series

To compare several independently distributed time series, I decided to take a compare their coefficient of variations. Is there any better way to compare them and even group them?
11. Comparing the Power and Effect Size from Different Studies

Hi there Talk Stats Community, I am an undergraduate research assistant. Currently I am doing research on a project, and our results have indicated something that is quite different from previous findings. We have used a more specific and sensitive test to prove that a particular microbe...
12. Dissertation Results Comparisons - which SPSS method should I use?

Hi everyone, I'm in my final year as a Psychology student aspiring to be a cognitive neuroscientist (accepted to birmingham university provided I get my 2.1 class honours :D), firstly I'd like to thank you for your time to read this (especially since there is a lot of reading to be done, I...
13. comparing two dose(inhibition) respose curves log vs log log

I'm not a stats person, so I need some help. I am looking for a statistics model to compare one dose(inhibition) response curve to the log space of that same curve. The trick is, in order to analyze the data, we have to take the observed concentrations and RFU's and log transform them. We...
14. Comparing a sub-population to its overall population?

Hi there, I am collecting data from a population of about 150 or so, and also from a subpopulation within that of 10-15 which are receiving a specific treatment. I am aiming to compare their scores on the same measure, to see if this population receiving treatment is truly 'special' in some...
15. Comparison of two treatments (paired and unpaired)

Hi all! I'm working on my Master thesis and need to make sure I'm not doing it wrong. My research: Are answers to questions a and b significantly different from one another, and why? Questions a and b are answered on a scale from 0 to 10. My data: 153 survey responses, split into 3...
16. Compare regression coefficients within one sample

Hey, I run two univariate linear regressions within one sample (same subjects, two different conditions). Now I would like to know how to compare the regression coefficients in order to find out whether they differ significantly. All of the methods I find apply to a case with two different...
17. comparing and accounting for temperature difference between two locations

Hi, I'm a student currently undertaking my dissertation. The aim of my research is to try to gain an understanding of what informs people's temperature perceptions, with a specific focus on cultural theory, although other sociodemographic questions were also asked in the survey. One of the...
18. Before and after comparison troubles

Hi! I'm having some trouble with my before and after comparison and hope you guys can help me! I have asked the same group of respondents to answer questions about their wellbeing and their main travel mode before and after the introduction of a toll scheme. I want to be able to see if...
19. comparing "pooled" coefficients between different models

Dear all, I am running a mediation model with 6 continuous predictors and 2 mediators, separately for boys and girls. I want to test if the regression coefficients differ between gender models. For that, I have found the equation b1-b2/SQRT(s.eb1^2+ s.e.b2^2) and this works fine...
20. P

sample size for control and treatment groups

hello everyone, I am in the process of designing an agricultural experiment in which I want to compare a series of variables between a group of manufacturers who use a mobile telephone app (n=15,000) is my treatment group and another group that does not (n=100,000) which is my control group...