Matrix Question

[Steven G]

What on earth does the 1 mean in S1??
Just thinking what it could be and was wondering if it the matrix with all 1's in it?

 

[Steven G]

OK, it is the n-vector with all 1s

 

[HallsofIvy]

That would have been my guess!

 

[Deleted member 4993]

OK, it is the n-vector with all 1s

That would mean that:

All the patients (all the i s) are exhibiting all the symptoms (all the j s).

 

[Dr.Peterson]

That would mean that:

All the patients (all the i s) are exhibiting all the symptoms (all the j s).

No, that would be if all the entries of S were 1.

If 1 is a column vector with all 1's, then the product S1 would be a column vector containing the number of symptoms each patient has. I think.