# difference of means

1. ### Comparing differences between groups in different samples - which statistical test to chose?

Hello everybody I am doing some research in sleep medicine where I compare the test results of different sleep and vigilance tests. Within these different vigilance test results, the data is sorted in different patient groups. Since my data is non-normally distributed, I performed a...
2. ### Bar graph showing difference of means

Is there a way to create a bar graph, with multiple DVs, showing the difference between the means of the IV? I have two experimental conditions and would like to display the mean differences in one bar graph. The dependent variables are several different test scores and therefore each have a...
3. ### How to correct the means of a variable in 4 groups matlab

I compute the mean of the variable Y in 4 groups (A B C D) that differ for age, gender and body mass index (BMI). n=89 | n=375 | n=302 | n=166 | GROUP A | GROUP B | GROUP C | GROUP D | MALE 46...
4. ### Seems so simple: differences... and yet but not between groups... Which test to use?

Hi there :) This seems so simple I'm hoping someone can help me! :confused: I've got the mean values for no. effective alleles in 5 different populations of fish. So, 5 rivers, each with a mean value... and I'm trying to give a statistical value as to whether there are significant...
5. ### Importance of Normality Assumption for Hypothesis testing methods

Hello everyone! Can someone please share their thoughts on the following question with me. Methods of hypothesis testing usually has a normality assumption for underlying data or for residuals in the case of regression. Why is this assumption important for either case; i.e. for...
6. ### CI for difference between means

Control: n=13, Mean=32.77, StDev=32.77, SEMean=3.328 Treatment: n=16, Mean=42.01, StDev=17.2, SEMean=4.3 Point Estimate for treatment - control = 9.24 df = 27 What is the 98% CI? I calculated the ME as 13.45 and the CI as (-4.21, 22.69) Is this correct?
7. ### Confidence Intervals for Pairwise Independant Normally Distributed Samples

Good day, I have been thinking over this exercize for a couple of hours now and I have trouble finding a starting point. Suppose that X1,i iid∼ N(µ1, σ²), X2,i iid ∼ N(µ2, σ²), that the samples are pairwise independent, and that σ is known. Derive a 1 − α conﬁdence interval for µD = µ1 − µ2 I...
8. ### Finding a value to show there's significant differnece between two population means

I'm working with two data sets and want to compare the difference of means between two particular rankings between two different years. My boss wants me to find a number to prove there is significant difference between these means. I am wondering if there is a statistics equation to find this...
9. ### Difference of mean with unequal sample sizes and nesting (and non-independence!)

Hello: I've never posted here before; hopefully this query isn't redundant. (I have tried to look through previous posts for an answer!). My problem involves difference of means, unequal sample sizes, and nested groups. The basics: I want to know whether the difference between two means is...