Instruction: Given a question and its related document, determine if the question is answerable by analyzing the information in the document. Output yes if the document addresses the question, or no otherwise.

Input:
Question: are these okay to use over old tiles in the shower? How slippery?
Document: I purchased these tiles in anticipation of having some work done on my pool. Turns out I didnt need them but they are good to have on hand in the future.
I lost some more pool tiles over this past hard winter and only had a few spares left. I ordered one sheet of these to see if they were the same. Almost perfect match (slightly more shiny) and after a season of being subjected to the pool chemicals, etc.I'm satsified they will look identical. I've ordered several sheets more to have some spares. Shipping was prompt and tiles were well  packed.
I didn`t think it was possible to get porcelain in a blue glaze like this. I have looked and looked and this is the only tile in it`s class. I recommend it without reservation.
Answer: no