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1 vote
1 answer
525 views

Residuals not normal due to random effects structure

I am new to mixed-effect models and statistics, and I need to do a project for my thesis using mixed-effect modeling techniques. My research aims to model how cardiovascular risk scores change over ...
0 votes
1 answer
59 views

How to produce synthetic (fake) data knowing the correct fit parameters?

For cross-checking purposes, if I want to check that a NonlinearModelFit performed in Mathematica is producing the correct standard errors, I would need to produce simulated data based on the fitted ...
2 votes
1 answer
417 views

Linear Regression Coefficient Interpretation [closed]

I have a regression problem: regress y on x1 x2 y: Sales revenue, x1: is_holiday (dummy variable), x2: another continuous variable (note that this is just the ...
2 votes
0 answers
1k views

How can I compute the lower and upper bounds of a confidence interval in a linear regression problem?

I am completing a university statistics assignment on the Mathematica program, and this is the initial question: "The Medical Research Council wanted to evaluate the effects of different dosages of a ...
2 votes
1 answer
4k views

Best multivariate polynomial regression

I have a dataset (x,y) where x is a n-dimensional vector and y is an m-dimensional vector. (m=3, n>2) My goal is to find the best polynomial in x fitting the (x,y) dataset. The dimension of x is ...
1 vote
1 answer
1k views

Normalizing error variance scale

Imagine we have two sets of data m1 and m2. m1 components have the dimension of [m^2/s] and m2 components are measured in [cm^2/s]. e.g. ...
3 votes
1 answer
2k views

How to calculate confidence and prediction bands for a linear regression using Mathematica?

I need to calculate confidence and prediction bands for a linear regression that is in the general form of $y=ax$, where $a$ is the multiplier and $x$ the variable. I found a code in http://...