The following data gives the information on the observed lifetime (in hours) of 225 electrical components:
Life time (in hours)0−2020−4040−6060−8080−100100−120Number of components103552613829
Determine the modal lifetime of the components.
65.62
Modal class = 60-80, l = 60, f1 = 61, f0 = 52, f2 = 38 and h = 20
Mode=l+(f1−f02f1−f0−f2)×h⇒60+(61−52(2×61)−52−38)×20⇒60+(932×20)=65.62