Q.3.
6 Marks
The time to failure of a typical household refrigerator has the following PDF:
f(x)={(0.003t^(2)-0.06t+0.3 for 0<=t<=10yr),(0 elsewhere ):}
(a) What is the reliability of the refrigerator for the first year?
(b) Determine the design life if a 0.90 reliability is required.
(c) Find the hazard rate function. Is it increasing or decreasing?
(d) The company claims the appliance is highly reliable by quoting the MTTF. What is the MTTF? What percentage of the refrigerators will survive the MTTF?
(e) The company has a 1-month warranty period. What is the probability that a refrigerator will fail during the first month? Given the refrigerator has survived its first month (the warranty period), what is the probability that it will survive the rest of the year?
Q.3.
6 Marks
The time to failure of a typical household refrigerator has the following PDF
(0.003t2 -0.06t +0.3 fx 0
for 0 t10 yr elsewhere
(a) What is the reliability of the refrigerator for the first year? (b) Determine the design life if a 0.90 reliability is required. (c) Find the hazard rate function. Is it increasing or decreasing? (d) The company claims the appliance is highly reliable by quoting the MTTF. What is the MTTF? What percentage of the refrigerators will survive the MTTF? (e) The company has a 1-month warranty period. What is the probability that a
refrigerator will fail during the first month? Given the refrigerator has survived its
first month (the warranty period), what is the probability that it will survive the rest of the year?