Sampling distribution

A prominent bank located in Kuala Lumpur has some 400,000 users of its credit cards scattered throughout Malaysia. The application forms for the credit card asked for the usual information about name, address, income, level of education and so on that is typical of such applications. The bank is currently interested in determining if there is any directional relationship between the frequency of card usage and the amount of credit charged on the card for various purchases made within a month, i.e. the more frequent the card is used, the higher is the credit amount charged on the card.