multivariate analysis

Hi, I am writing my thesis for medicine about postoperative complications of a disease (IBD). The dependent variable in this case is whether the patients had a post-operative complication or not (binary) within 30 days of their operation. The sample size for my study is n = 62. I have...

Hi there. This will be my first post on the forums, I'm a Psychology student currently conducting research at an internship. We treat IDD (Intellectual Developmental Disorder) patients with different types of therapy, and I've been assigned to study the dosage components of DBT (Dialectic...

I have 7 subscales/dependent variables and I want to find the relationship/effect of 1 two-group qualitative variable, a quantitative covariate, and their interaction on those 7 DVs. I ran 7 hierarchical regressions (with the interaction in block 2), and 7 ANCOVAs to test these and in all cases...

Hi all, I have a data set with 3 proposed dichotomous independent variables: sex (male or female), side (left or right), and region (lower or upper). I want to know which are significant / affect my dependent variable: distance. Apparently, in the medical research community, it is common to...

Hello everyone! I just started modelling and I have a question about how to interpret my results. I built 3 models, two univatiates (Z ~ bX + e; Y ~ bX + e) and one multivariate model ( Z, Y ~ bX + e). In both univariate models 'X' was not relates with 'Z' or 'Y', but it was in the...

Hi all, I'm interested in the potential effects of water pollution on feather color of a bird. For this, I calculated 4 color variables for each individual (brightness, hue, blue chroma and UV chroma), which are my 4 dependent variables. My independent variables (explanatory) are the...

The same participants are exposed to two different screen sizes 27" (stimulus A) and screen size 9.7" (stimulus B). Independent var is "screen" with two levels - sizes. After exposure to stimulus A, they fill two questionnaires to answer dependent variables Y1 and Y2. After that, they are...

Dear all, I have the following biological data: 1st variable (continuous, normally distributed): concentration of a hormone in blood 2nd variable (continuous): age of donors 3rd variable (categorical): genotype (control vs mutation-carrier) 4th variable (categorical): gender (male vs...

Let, \mathbf y_i = \mathbf X_i\mathbf\beta + \mathbf Z_i\mathbf b_i+ \mathbf\epsilon_i, where \mathbf y_i\sim N(\mathbf X_i\mathbf\beta, \Sigma_i=\sigma^2\mathbf I_{n_i}+\mathbf Z_i \mathbf G\mathbf Z_i'), \mathbf b_i\sim N(\mathbf 0, \mathbf G), \mathbf\epsilon_i\sim N(\mathbf 0...

Let \mathbf x is a (p\times 1) vector, \mathbf\mu_1 is a (p\times 1) vector, \mathbf\mu_2 is a (p\times 1) vector, and \Sigma is a (p\times p) matrix. Now I have to show -\frac{1}{2}(\mathbf x-\mathbf\mu_1)'\Sigma^{-1}(\mathbf x-\mathbf\mu_1)+\frac{1}{2}(\mathbf...

Hello to everyone, i need some help with my statistical analysis. I have two different pharmacokinetic parameters. They result from two different models applied on the same data. These data are baseline and follow up data of 20 subjects. To sum up, for each subject, i have 4 measures: - two...

I am a graduate student. I have a 6 credit thesis and I am interested in the field of longitudinal and Bayesian. My supervisor said me to choose my topic. But I am not understanding if I choose a topic how can I know what is the scope (further extension) of this topic because I can't only...

Hi, I need to find the impact of mathematics on student performance. I have only the student exam marks for mathematics and all the other subjects. What are the statistical methods that can be used for this situation other than correlation and regression? According to my point of view, I...

I have been asked to analyse the following data using linear analysis, mean standard deviation and ANOVA. However the data presented is supposed to be continuous but for small values they have grouped them as less then 5 almost like discrete. They represent the ages of children using...

I have been issued data on chemicals in air samples from around the world, elements parts per million. Some of the stations have returned data where if the parts are really small <20 they have recorded the result as -20. Which I do not know how to include in my analysis of the data. I was...

Hi everyone! I have a data set of multivariate data (4 treatments, 3 samples per treatment, 14 variables, the variables are concentrations of different metabolites). I have 2 repetitions of the same experiment, performed in the exact same way. I would like see if the two data sets from the two...

Hello statistics experts! I couldn't find an answer to my question so I thought that one of you might know: I have 14 risk sources, like nuclear power plants (let's call them "objects"), and participants judged them on 14 characteristics (e.g., potential danger). Now, I would like to create...

Hi, I've data set collected from 700 sheep farms from 5 regions of England (north, south, East, West, Central). The aim is find out if climate variables (maximum temperature, minimum temperature, rainfall) are predictors for animal disease in the regions, so the outcome variable (y) = number of...

I have a data set of multivariate data (4 treatments, 3 samples per treatment, 14 variables, the variables are concentrations of different metabolites). I have 2 repetitions of the same experiment, performed in the exact same way. I would like see if the two data sets from the two repetitions...

Hi Is it a function that could be used in R to run Chauvenets criterion to reject outliers in a data set? Or does it have to be done manually by calculating the mean, standard deviation, probability etc? Also for multivariate analysis in R, what type of analyses can you use when one...