[R-meta] A question about meta-regression Analysis

[Hamed Kianmehr]

Thank you for your prompt response.

For the test, do you mean the value of coefficient(s) (attached file)?  if
yes, how can I find it better than rest of them?

On Fri, Jul 13, 2018 at 1:02 PM, Viechtbauer, Wolfgang (SP) <
wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:

> Thanks. Well, hard to say if these data are suggestive of a quadratic
> trend based on visual inspection.
>
> The test of the coefficient for 'poly(year, 2)2' tells you whether the
> quadratic model fits significantly better than just the linear model.
>
> Best,
> Wolfgang
>
> -----Original Message-----
> From: Hamed Kianmehr [mailto:hkianme1 using binghamton.edu]
> Sent: Friday, 13 July, 2018 18:39
> To: Viechtbauer, Wolfgang (SP)
> Cc: r-sig-meta-analysis using r-project.org
> Subject: Re: [R-meta] A question about meta-regression Analysis
>
> ATTACHMENT(S) REMOVED: Plot.jpg
>
> Thank you for your response.
> Please see the attached file regarding the plot.
>
> On Fri, Jul 13, 2018 at 12:35 PM, Viechtbauer, Wolfgang (SP) <
> wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:
> Dear Hamed,
>
> Please post in plain text format. I cannot see any plot. Either attach it
> as a separate image file or post it somewhere else and provide a link.
>
> As for 2 - If you use poly(), try:
>
> preds <- predict(res, transf = transf.ilogit, newmods = unname(poly(years,
> degree=2)))
>
> Best,
> Wolfgang
>
> -----Original Message-----
> From: R-sig-meta-analysis [mailto:r-sig-meta-analysis-
> bounces using r-project.org] On Behalf Of Hamed Kianmehr
> Sent: Friday, 13 July, 2018 16:03
> To: r-sig-meta-analysis using r-project.org
> Subject: [R-meta] A question about meta-regression Analysis
>
> I have some questions regarding the meta-regression analysis. I have the
> database on the proportion (Below bubble plot). My advisor asked me to do
> the polynomial regression. I have two questions:
>
> 1- Is it any polynomial regression pattern in this data?
> 2- I wrote below code but I couldn't get the line, Could you help me?
> ----------------
> res<-rma(yi=y, vi=s2, data=data, method="DL",mods = ~ poly(year, degree=2))
> years <- 1989:2016
> preds <- predict(res, transf = transf.ilogit, newmods
> =cbind(years,years^2))
> wi <- 0.5/sqrt(data$s2)
> wi <- 0.5 + 3.0 * (wi - min(wi))/(max(wi) - min(wi))
> plot(data$year, transf.ilogit(y), cex=wi,xlab="Year",ylab="Patient
> Expectation (%)")
> lines(years, preds$pred)
>
> --
> Best Regards,
> Hamed Kianmehr, Ph.D. Candidate
> Department of Systems Science and Industrial Engineering
> The State University of New York at Binghamton
>



-- 

Best Regards,

Hamed Kianmehr, Ph.D. Candidate

Department of Systems Science and Industrial Engineering

The State University of New York at Binghamton

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