The pipe company is one of several domestic manufacturers of PVC pipe

The pipe company is one of several domestic manufacturers of PVC pipe. The quality control
department gathered a sample of size n = 600 10-foot lengths. At a point 1-foot from the end
of the pipe, they measured the outside diameter. The mean average diameter and standard
deviation are respectively 14.0 inches and 0.1 inches.
The shape of the distribution is not known. At least what percent of the 10-foot lengths
will fall in between 13.85 and 14.15 inches?
The shape of the distribution is not known. At most what percent of the 10-foot lengths
will fall outside 13.85 and 14.15 inches?