This part of IEC 62552 specifies the essential characteristics of household refrigerating appliances cooled by internal natural convection or forced air circulation, and specifies test methods for checking the characteristics. This part of IEC 62552 describes the methods for the determination of performance requirements. Although there is some commonality in the set-ups for different tests (and so it may be an advantage to apply them all to one sample), these are separate tests to evaluate specific characteristics of the sample being tested. This part of IEC 62552 does not specify a procedure to generalise the results from sample test results to a prediction of the characteristics of the whole population from which that sample was selected.