Question 1
Ten high-technology batteries are tested for 200 hours each. One failed at 20 hours; all others completed the test. FR(%) is ________ and MTBF is ________.
10%; 1/1820
90%; 1/1820
10%; 1820 hours
10%; 1980 hours
Question 2
A product has three components, A, B, and C, with reliabilities of 0.95, 0.98, and 0.995. Engineers intend to put a redundant component A that has reliability 0.70. With this change, system reliability will
fall by 20%
fall by 10% or less
rise
cannot determine from the information provided.
Question 3
What is the reliability of the three components connected in series shown below?
0.799425
0.85
0.91333
0.95000
Question 4
DuLarge Marine manufactures diesel engines for shrimp trawlers and other small commercial boats. One of their CNC machines has caused several problems. Over the past 30 weeks, the machine has broken down as indicated below.
|
Number of breakdowns per week
|
0
|
1
|
2
|
3
|
4
|
|
Frequency (Number of weeks that breakdowns occurred)
|
8
|
3
|
5
|
9
|
5
|
What is the expected number of breakdowns per week?
1
2
6
10
Question 5
DuLarge Marine manufactures diesel engines for shrimp trawlers and other small commercial boats. One of their CNC machines has caused several problems. Over the past 30 weeks, the machine has broken down as indicated below. Each time the machine breaks down, the firm loses an average of $3,000 in time and repair expenses.
|
Number of breakdowns per week
|
0
|
1
|
2
|
3
|
4
|
|
Frequency (Number of weeks that breakdowns occurred)
|
8
|
3
|
5
|
9
|
5
|
What is the expected breakdown cost per week?
$1000
$2000
$6000
$10000
Question 6
DuLarge Marine manufactures diesel engines for shrimp trawlers and other small commercial boats. One of their CNC machines has caused several problems. Over the past 30 weeks, the machine has broken down as indicated below. Each time the machine breaks down, the firm loses an average of $3,000 in time and repair expenses. If preventive maintenance were implemented, it is estimated that an average of only one breakdown per week would occur. The cost of preventive maintenance is $1,000 per week.
What is the weekly total maintenance cost of this program?
|
Number of breakdowns per week
|
0
|
1
|
2
|
3
|
4
|
|
Frequency (Number of weeks that breakdowns occurred)
|
8
|
3
|
5
|
9
|
5
|
$1000
$3000
$4000
$6000
Question 7
Century Digital Phone advertises phone battery life (on standby) of up to three days. The standard deviation is thought to be five hours. Tina Talbot, an employee at CDP, tested 10 of these batteries for 72 hours. One failed at 40 hours; one failed at 62 hours; one failed at 70 hours. All others completed the test. FR(%), FR(N), and MTBF are ___ , ___ , ___ , respectively:
30%, 0.09112, 296.2 hrs
33%, 0.0633, 218.2 hrs
30%, 0.005444, 118 hrs
30%, 0.00444, 225.3 hrs
Question 8
1. The Everstart is a battery with an intended design life of 72 months. Stephanie Bradley recently put five of these batteries through accelerated testing (the company couldn't wait six years) to simulate failure patterns. The test results had one failure at 26 months, one failure at 32 months, one failure at 50 months, and one failure at 62 months. FR(%), FR(N), and MTBF are ___ , ___ , ___ respectively.
76%, 0.0193, 53.5
80%, 0.0215, 60.5
80%, 0.0165, 60.5
80%, 0.0165, 82.3
Question 9
1. 1. The academic service commonly referred to as "registration" consists of several smaller components: advising, registration for courses, fee assessment, financial aid calculations, and fee payment. Each of these modules operates independently and has some probability of failure for each student. If the five probabilities which accompany these services are 95%, 90%, 99%, 98%, and 99%, what is the "reliability" of the entire product from the student's perspective-the probability that all five will work according to plan?
0.89126
0.82123
0.73491
0.71121
Question 10
A product has four components A, B, C, and D. The finished product must have a reliability of .95. The first three components come from a supplier, and have reliabilities of .99, .98, and .995. The fourth component is being designed now. What must the reliability of component D be in order to meet the product reliability condition?
0.9518
0.9612
0.9732
0.9841