Defects obtained during the various phases of manufacturing a product, play a critical role from developing to shaping it to the final one. It may so happen that the list of defects surfacing may be extremely large. In such a case, it is difficult for the organization to address each of these defects as this involve extra resources (man, material, money, machine and time) which in turn, soars up the quality investments. Again, no address to these issues will lead to a poor product eventually leading to the product’s failure. So, it is necessary that these defects are well defined, managed and analyzed effectively such that critical defects are filtered out. This helps making the entire defect prevention procedure cost and effort effective. Keeping these points in view, it is important to perform the analysis through multiple approaches and prioritize the defects into critical ones. In this paper an attempt has been made to analyze a list of production defects using multiple defect analyzing approaches and sieve out the exact sources of variations. For this purpose, the defects obtained during the manufacturing of thermoformed refrigerator liners have been taken. Quality improvement approaches like Six Sigma have been used together with statistical tools like FMEA, Test of Hypotheses to perform the analysis.