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Questions tagged [mixed-random-variable]

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2 votes
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R - Not sure about nested factor in linear mixed-effect model (lmer)

I am currently studying the presence of biological markers in post-mortem brains of healthy individuals compared to Alzheimer patients. I am not entirely sure I am using the correct design for my ...
Mat's user avatar
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0 answers
14 views

What is this mixed random variable’s variance? [duplicate]

X ∼ Uniform(a,b), a<b (Discrete) where f(x)=1/n where n=b-a+1 and Y ∼ Uniform(c,d), c<d (Continuous) where g(y)=1/d-c. X and Y are independent. Let z = x - y. I was able to find the E(Z), ...
raffaello.sanzio's user avatar
0 votes
0 answers
60 views

What is this hybrid(mixed) random variable’s variance?

X ∼ Uniform(a,b), a<b (Discrete) where f(x)=1/n where n=b-a+1 and Y ∼ Uniform(c,d), c<d (Continuous) where g(y)=1/d-c. X and Y are independent. Let z = x - y. I was able to find the E(Z), ...
raffaello.sanzio's user avatar
0 votes
0 answers
19 views

What is the consequence of not measuring time as a random effect in an MLA?

I'm conducting a multilevel regression analysis (mixed model) with time as the levels. My teacher wanted me to measure time as both a fixed and as a random effect. However, it turned out I couldn't ...
user395471's user avatar
1 vote
1 answer
53 views

Cumulative distribution function of mixed variables

Given the probability density function: $ \begin{equation} f_{X, Y}(x, y)=\begin{cases} \frac{xy}{3}, & \text{if } x=1,2,3 \text{ and } 0 < y < 1.\\\\ 0, & \text{otherwise}. \...
dori's user avatar
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1 vote
0 answers
37 views

Mixed linear model to fit soil samples taken over two sampling points

I have the following data for two different sampling points: proteins from three different drought intensities (control, moderate and severe), and also using two diferent treatments (sterilized and ...
Tábata Aline Bublitz's user avatar
2 votes
0 answers
319 views

Multilevel/ Mixed Model / HLM Centering Interactions Level 1 and Level 2 Cross-Level

I am having some trouble with the literature on the correct model specification for my question. Here is the setup: I have a multilevel model with a variety of variables at level 1 and a single level ...
bzh's user avatar
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1 vote
1 answer
81 views

Linear Mixed models: show that one paramter has an effect on outcome with two affecting parameters

I have a serie of analysis on 5 different specimens, with 2 different modifying parameters and one outcome. Both parameters have an effect on the outcome. My goal ...
ecjb's user avatar
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3 votes
0 answers
80 views

Density function of a dependent sum of products of normal random variables

Say we have a random variable $$ X = A_0 A_1 + A_0 A_2 + A_1 A_2, $$ which consists of normally distributed independent random variables $A_0, A_1, A_2 \sim \mathcal{N}(0,1)$ with probability ...
Radim Zedka's user avatar
6 votes
2 answers
649 views

does convolution of a probability distribution with itself converge to its mean

Suppose we have a probability distribution $f(x)$ with a finite support $[a,b]$. If we take the probability convolution of $\lambda f $ with $(1-\lambda)f,0 <\lambda<1$ recursively for many ...
Emma's user avatar
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5 votes
2 answers
2k views

Mixed effect model with interaction

I am trying to explore the effects of an intervention on different outcome measures over time. In this example I evaluate the differences in the log-transformed data of my response variable (named: ...
Anna Ferrusola Pastrana's user avatar
1 vote
1 answer
840 views

I'm lost in Crossover design-repeated measurements and mixed modelling

I am searching for days now, in what I think is a repeated measurements crossover design but I think I got mixed up reading up on it and I'm now going in circles so I was wondering if anyone could ...
Tsitsi_Catto's user avatar
8 votes
1 answer
291 views

What is the distribution of $Z(X+Y)+XY$?

Given that $$ X \sim \mathcal{N}(0,1) \\ Y \sim \mathcal{N}(0,1) \\ Z \sim \mathcal{N}(\mu,1) $$ are independent, what is the PDF of $$ Z(X+Y)+XY $$ I tried to transform this expression to $$ \frac{1}{...
Jiang Liu's user avatar
-1 votes
0 answers
23 views

How can $X$ be a discrete random variable? [duplicate]

Suppose that the cumulative distribution function of discrete random variable $X$ is given by, $$F(x) = \begin{cases} 0 & \text{$x$ < 0 } \\[1.5ex] \dfrac{x}{4} & \text{$0 \leq x<1$}\\[...
D ake's user avatar
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