On Tue, Jun 18, 2013 at 10:43 AM, Ross Ahmed <rossahmed@googlemail.com>wrote:

> I靶e made this varying intercept and varying slope model:
>
> lmer(angle ~ temperature + (temperature | recipe), data=cake)
>
> I two questions:
> 1. Does this code made exactly the same model as above: lmer(angle ~
> temperature + (1 + temperature | recipe), data=cake)?
>

Yes.  As a linear model formula

temperature

is equivalent to

1 + temperature.

If you wanted to get the indicators for the levels of temperature instead
you suppress the intercept term using

0 + temperature

or

temperature - 1

I prefer the first form.


> 2. Why does temperature have L, Q, C, ^4 and ^5 in the output?
>

temperature is an ordered factor and the default contrasts for an ordered
factor are orthogonal polynomial contrasts.

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