Probability and Significance
1) A fair coin is tossed 10 times. What is the probability of 7 or more heads occurring, to three significant digits?
A. .828
B. .172
C. .055
D. .056
2) Failures per day for a computer network follow the Poisson distribution with mean 0.3. What is the probability that two or more failures occur in
a day, to three significant digits?
A. .222
B. .0369
C. .0900
D. Cannot be determined from the information provided.
3) The lifetime of an electronic component follows the exponential distribution with MTBF of 400 hours. What is the probability that the item fails in the first 48 hours of life, to three significant digits?
A. .904
B. .113
C. .096
D. .125
4) The lifetime of an item follows the exponential distribution, with MTBF of 400 hours. What is the median life, to three significant digits?
A. 277 hours
B. 253 hours
C. 400 hours
D. Cannot be determined from the information provided.
5) The weight of a component produced by a production line follows a normal distribution with mean 1.5 Kg and standard deviation of 25 grams. What is the probability that a component weighs less than 1.510 kg, to three significant digits?
A. .655
B. .484
C. .516
D. .526
6) A roulette wheel has 18 black bins, 18 red bins, and 2 green bins. A ball is equally likely to fall in any bin, and each spin is independent. Two spins are made. To three significant digits, what is the probability that a roulette ball falls into two red bins?
A. .277
B. .224
C. 0.25
D. .237
7) The same roulette wheel is spun two more times. What is the probability that a ball fall in a green bin at least once in the two spins, to three significant digits?
A. .997
B. .104
C. .102
D. .100
8) If at least one child in a family with 2 children is a boy, what is the probability that both children are boys, to three significant digits? Assume boys and girls are equally likely.
A. 0.750
B. 0.333
C. 0.667
D. 0.500
9) Two fair dice are tossed. What is the probability of not getting a 7 or an 11?
A. 5/7
B. 7/9
C. Cannot be determined from the information given.
D. 5/6
10) Consider a fair roulette wheel with 18 red, 18 black, and 2 green bins. How many spins on average will occur until the ball lands in a green bin?
A. 18
B. 19.5
C. 19
D. Cannot be determined from the information given.