I often confuse symbols :, |, / and * in the R formulas, particularly when fitting mixed models with lme4. Can somebody explain clearly the differences between them?

Later edit by @amoeba (Jan 2018): this question had a long and extremely confusing R code. I cut it all out for the benefit of future readers. Please see edit history if interested.

  • 3
    $\begingroup$ Just to link to a related thread where Mike Lawrence provided a pretty nice overview of R's formula for mixed-effects models. $\endgroup$
    – chl
    Commented Nov 15, 2011 at 21:19


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