PROBLEM 1.23SOLUTION
Repetition through repeated measurements made under a fixed set of operating conditionsprovides a measure of the time (or spatial) variation of a measured variable.Replication through the duplication of tests conducted under similar operating conditionsprovides a measure of the effect of control of the operating conditions on the measuredvariable.Repetition refers to repeating the measurement during a test.Replication refers to repeating the test (to repeat the measurements).