Product quality is often measured in terms of purity and grade of material used in technical perfection of design and exciting stands.
Kolter (1998), define product quality as the degree of excellence a product possess with regard to physical properties. ( such as the prestige of the brand name) It may be high, low, medium, good, bad, fair, excellent, first-class etc.
The quality of product or degree of excellence varies greatly for virtually all customers and industrial goods. The very reason for the wide variation in product quality is that consumer differ greatly in their purchasing power.
While we occasionally do find customers with high income who purchase products that are low in quality ( the upper income family buys used tyre, used furniture, used shoes etc) a correlation does exist between purchasing power and the quality of products bought.