[R-meta] Follow-up the coding question for meta-regression

[Michael Dewey]

Comments in-line

On 11/12/2023 23:21, 英文科陳品誠 via R-sig-meta-analysis wrote:
> Dear Wolfgang,
>       Sorry for another interruption. I ran into two more questions. First,
> when I was trying to write the code like this:
> 
> dat$duration <- cut(dat$duration, breaks=c(0,4,8,12),
> labels=c(“NA”,”S”,”M”,”L”), right =FALSE)
> 
>     and the system told me that “x has to be numbers”, what should I do then?
>      (p.s. I am pretty sure that the part “breaks” is also wrong…)
> 
>     **Name of the moderator: duration
>         The distinction between the moderators:
>          NA = not provided
>          S (short) = 0-4 weeks
>          M (medium) = 4-8 weeks
>          L (long) = 8 weeks or above


So R is correct, that variable is not numeric but either character or 
factor. You would not need breaks either.

> 
>      and my second question is that, here is one of the interaction I
> performed:
>      [here I was trying to find out the interaction between the moderator
> "instruction type" and "research design", and instruction type was coded
> "ins" and with two categorical value "D (definition)" and "C(context)";
> research design was coded "rede" and with two categorical value "D
> (traditional)" and "O (others)"]
> 
> Model Results:
>              estimate      se     zval    pval    ci.lb   ci.ub
> intrcpt       0.9482  0.3581   2.6476  0.0081   0.2463  1.6501  **
> insD          0.5142  0.4281   1.2012  0.2297  -0.3248  1.3532
> redeO         0.4920  0.6163   0.7984  0.4246  -0.7158  1.6998
> insD:redeO   -1.2206  0.8256  -1.4784  0.1393  -2.8388  0.3976
> 
> 
> Does the last line "insD:redeO" already means the interaction was not
> significant with the p-value of 0.1393? Do I need to do the "anova(res.il,
> btt3:4)" as suggested in the website?

Yes, that interaction is not adding anything important in your model.

Michael

> 
> Nick
> 陳品誠 (Nick Chen)
> Email: t571 using wlgsh.tp.edu.tw <t5741 using wlgsh.tp.edu.tw>
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Michael