getting a submatrix of all true

[John Hunter]

>>>>> "Terry" == Terry Reedy <tjreedy at udel.edu> writes:


    Terry> Statisticians have tried a variety of approaches.  Googling
    Terry> for ' statistics "missing data" 'will give you some leads
    Terry> if you want.

I have done some searching.  I'm familiar with the common methods
(delete every row that contains any missing, replace missing via mean
or regression or something clever) but haven't seen any discussion of
dropping variables and observations together to yield data sets with
no missing values.  Have you seen something like this?

John Hunter