6.33 A coin is weighted so that heads is twice as likely to appear as tails. The
probability that two heads occur in four tosses is:
a. 0.15
b. 0.35
c. 0.45
d. 0.75
6.34 It is given that 20% of all employees leave their jobs after one year. A
company hired seven new employees. The probability that nobody will
leave the company after one year is:
a. 0.1335
b. 0.2315
c. 0.3815
d. 0.6510
6.35 If four fair coins are tossed simultaneously, the probability that at least
one head appears is:
a. 0.1335
b. 0.5635
c. 0.7815
d. 0.9375
6.36 For unit normal distribution, the probability that (x > 3) is:
a. 0.0013
b. 0.0178
c. 0.1807
d. 0.5402
6.37 Scores in a particular game have a normal distribution with a mean of 30
and a standard deviation of 5. Contestants must score more than 26 to
qualify for the finals. The probability of being disqualified in the qualify-
ing round is:
a. 0.121
b. 0.212
c. 0.304
d. 0.540
6.38 The radial distance to the impact points for shells fired by a cannon is
approximated by a normal Gaussian random variable with a mean of
2000 m and standard deviation of 40 m. When a target is located at 1980
m distance, the probability that shells will fall within ± 68 m of the target
is:
a. 0.2341
b. 0.3248
c. 0.5847
d. 0.8710