The life in hours of a thermocouple used in a furnace is known
to be ap-
proximately normally distributed, with standard deviation
σ
= 20 hours. A
random sample of 15 thermocouples resulted in he following data:
553, 552,
567, 579, 550, 541, 537, 553, 552, 546, 538, 553, 581, 539,
529.
Use the 5 steps in the testing procedure to solve following
question:
a) Is there evidence to support the claim that mean life exceeds
540 hours?
Use a...