Calculate the reliability of the item for the time interval concerned using the expression:

Where:

R(t)= Reliability, i.e., the probability that an item will perform its required function for time under the specified conditions.

e= The base of the natural logarithms (2.7183).

λ= The predicted failure rate of the item (Table 3-1).

t= The specified time interval at risk.

Examples are shown in the worksheets in Figure 3-1 and Figure 3-2.