[R] question about mean

[Wacek Kusnierczyk]

Rolf Turner wrote:
>
> On 9/02/2009, at 4:40 PM, Bill.Venables at csiro.au wrote:
>
>> Store your 'matrix' as a data frame.
>
>     Surely it's a data frame already, since ``school'' is character or
> factor,
>     and ``value'' is (must be?) numeric.
>
>     People have this unfortunate predilection to refer to data frames as
>     matrices, and this messes them, and everybody else, up.

still, a naive user's messing up data frames with matrices seems no
worse than an experrienced (?) r programmer's messing up lists with vectors.

vQ