probablity

1. Normalized Z-Table Questiong Is this right having problem with final answer

The amount of time it takes to produce a part is normally distributed with a mean equal to 10 second and standard deviation equal to 2 seconds. Fine the probability that the time it will take to produce any given part will be between 11 and 13.6 seconds. z = 11-10/2 = 1/2 = 0.5 z score =...
Let us consider a case where a ranked set sampling scheme from $n^2$ subjects has been adopted. There are a total of $n$ RSS blocks. So each RSS block contains $n$ subjects. We will follow up them. Some of these subjects will fulfill a certain criterion and get a treatment and some will not be...