Quick Print Inc. uses plain paper for copying needs. Weekly demand for that paper follows a normal distribution with mean $100$ and standard deviation $50($measured in reams$).$ Each week, a replenishment order is placed with its supplier and the order arrives one week later. All copying orders that cannot be satisfied immediately due to the lack of paper are backordered.

Suppose it uses $302$ boxes as its order$-$up$-$to level.

What is its in$-$stock probability?

Report your answer as a decimal to four decimal places.