Question
Asked 21st Nov, 2019

Integral for random vibration analysis?

Can anyone please help in verifying my numerator and denominator determinants to calculate the integral where m=6. I have attached the pdf of the reference material and also the form which i calculated. I need to make sure whether it is correct or not.

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Syntax for repeated measures, nested, mixed effects model using lmer() ?
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  • Hunter HowellHunter Howell
I'm trying to analyze temporal trends in a community of amphibians and looking to see what variables may be important in understanding declines.
My response is a single vector of ln transformed abundance (it was averaged across multiple "traps" at a plot and so is not integer based).
My variables of interest are
plot = the level of sampling (fixed effect nested within site; coded as chr)
site = multiple plots per site (fixed effect nested within region; coded as chr)
region = multiple sites per region (random effect; coded as chr)
wateryear = just the year the sample was taken (fixed effect, coded as a factor in the data frame for repeated measures )
depth.30 = mean water depth 30 days prior to sample (fixed effect)
Here is my current model =
model= lmer(LN_total_1 ~ WATERYEAR*(1|REGION)*depth30.mean +
(1|REGION:SITE) +
(WATERYEAR|PLOT2) + ## this is the issue term data=ANOVA_basefile2)
I'm trying to use the (WATERYEAR|PLOT2) to denote that the plot is what is being measured repeatedly, but I'm not sure if this is the correct way of specifying that. Is this the correct way to code for repeated measures in this syntax?
I also tried doing WATERYEAR:PLOT2 -1 which would check to see if there was a sig difference across plots for each wateryear (I think...?) but that returns, "Error in is.nloptr(ret) : objective in x0 returns NA"
Also for the (1|REGION:SITE) that's specifying the fixed effect of site within the random effect of region, correct?
Thanks for the help!
Is it possible to make a dummy variable for a within-subjects continuous covariate with two levels?
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  • Sebastian BromSebastian Brom
I am doing a repeated measures ANCOVA.
My independent variable is visual clutter measured as a between-subjects 2 levels categorical variable (Higher visual clutter versus lower visual clutter). For either the Higher visual clutter or lower visual clutter conditions, the participants in those respective groups either see the SPORT TYPE soccer first or basketball first (Note that everything is randomized so there are no order effects).
The dependent variable is consumer satisfaction and I have measured this separately for basketball and soccer. so two continuous dependent variables satisfaction (SATS) soccer and SATS basketball.
In the covariates box, I added the moderator: the continuous variable escapism and I added the interaction effect of visual clutter and escapism gender and age
My supervisor who is now unavailable told me in her feedback that if the difference in the means of sport type is significant I should include it as a covariate in the ANCOVA model.
But either I completely misunderstood her feedback or I am correct that it is impossible to create a dummy variable for a within-subjects continuous variable (sport type satisfaction).
And even so, in the repeated measures ANCOVA, the within-subjects test shows that there is no significant difference in means between basketball and football. But a simple paired t-test shows that for the higher visual clutter condition, there is a significant difference in means for the satisfaction levels between basketball and soccer while in the lower visual clutter condition there is not.
Can I drop sports-type based on the results of the repeated measures ANCOVA, the within-subjects effect being insignificant and conduct a regular ANCOVA afterwards?
My thesis is due in five days and I would deeply appreciate the help.
Sebastian Brom

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