Front housings for cell phones are manufactured in an inje process. The time the part is allowed to cool in the mold bef thought to influence the occurrence of a particularly troubles defect, flow lines, in the finished housing. After manu housings are inspected visually and assigned a score betv based on their appearance, with 10 corresponding to a perf corresponding to a completely defective part. An ex conducted using two cool-down times, 10 and 20 seconds, an were evaluated at each level of cool-down time. All 40 obse experiment were run in random order. The data are as follow 10 seconds 20 seconds WNOORNWVOW