Prestressed concrete cylinder pipe (PCCP) is a rigid pipe designed to take optimum advantage of the tensile strength of steel and the compressive strength and corrosive-inhibiting properties of concrete. PCCP, produced in laying lengths of 24 feet, is susceptible to major stress cracks during the manufacturing process. To monitor the process, 20 sections of PCCP were sampled each week for a 6-week period. The number of defective sections (i.e., sections with major stress cracks) in each sample is recorded in the table.

a. Construct a p-chart for the sample percentage of defective PCCP sections manufactured.

b. Locate the center line on the p-chart.

c. Locate upper and lower control limits on the p-chart. Does the process appear to be in control?

Transcribed Image Text:

РССР Week 1 2 4 5 6 Number of Defectives 1 0 3 1 2. 3.