# The exponential distribution is an example of

62. The net profit of an investment is normally distributed with a mean of $10,000 and a standard deviation of $5,000. The probability that the investor’s net gain will be at least $5,000 is _____________.

a) 0.1859

b) 0.3413

c) 0.8413

d) 0.4967

e) 0.5000

Ans:

Response: See section 6.2, Normal Distribution

Difficulty: Hard

63. Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. The probability that the project will be completed within 185 work-days is ______.

a) 0.0668

b) 0.4332

c) 0.5000

d) 0.9332

e) 0.9950

Ans:

Response: See section 6.2, Normal Distribution

Difficulty: Hard

64. Completion time (from start to finish) of a building remodeling project is normally distributed with a mean of 200 work-days and a standard deviation of 10 work-days. To be 99% sure that we will not be late in completing the project, we should request a completion time of _______ work-days.

a) 211

b) 207

c) 223

d) 200

e) 250

Ans:

Response: See section 6.2, Normal Distribution

Difficulty: Hard

65. Let x be a binomial random variable with n=20 and p=.8. If we use the normal distribution to approximate probabilities for this, we would use a mean of _______.

a) 20

b) 16

c) 3.2

d) 8

e) 5

Ans:

Response: See section 6.3, Using the Normal Curve to Approximate Binomial Distribution Problems

Difficulty: Easy

66. Let x be a binomial random variable with n=20 and p=.8. If we use the normal distribution to approximate probabilities for this, a correction for continuity should be made. To find the probability of more than 12 successes, we should find _______.

a) P(x>12.5)

b) P(x>12)

c) P(x>11.5)

d) P(x<11.5)

e) P(x < 12)

Ans:

Response: See section 6.3, Using the Normal Curve to Approximate Binomial Distribution Problems

Difficulty: Medium

67. The exponential distribution is an example of _______.

a) a discrete distribution

b) a continuous distribution

c) a bimodal distribution

d) a normal distribution

e) a symmetrical distribution

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Easy

68. For an exponential distribution with a lambda () equal to 4, the standard deviation equal to _______.

a) 4

b) 0.5

c) 0.25

d) 1

e) 16

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Medium

69. The average time between phone calls arriving at a call center is 30 seconds. Assuming that the time between calls is exponentially distributed, find the probability that more than a minute elapses between calls.

a) 0.135

b) 0.368

c) 0.865

d) 0.607

e) 0.709

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Hard

70. The average time between phone calls arriving at a call center is 30 seconds. Assuming that the time between calls is exponentially distributed, find the probability that less than two minutes elapse between calls.

a) 0.018

b) 0.064

c) 0.936

d) 0.982

e) 1.000

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Hard

71. At a certain workstation in an assembly line, the time required to assemble a component is exponentially distributed with a mean time of 10 minutes. Find the probability that a component is assembled in 7 minutes or less?

a) 0.349

b) 0.591

c) 0.286

d) 0.714

e) 0.503

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Hard

72. At a certain workstation in an assembly line, the time required to assemble a component is exponentially distributed with a mean time of 10 minutes. Find the probability that a component is assembled in 3 to 7 minutes?

a) 0.5034

b) 0.2592

c) 0.2442

d) 0.2942

e) 0.5084

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Hard

73. On Saturdays, cars arrive at Sam Schmitt’s Scrub and Shine Car Wash at the rate of 6 cars per fifteen minute interval. The probability that at least 2 minutes will elapse between car arrivals is _____________.

a) 0.0000

b) 0.4493

c) 0.1353

d) 1.0000

e) 1.0225

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Hard

74. On Saturdays, cars arrive at Sam Schmitt’s Scrub and Shine Car Wash at the rate of 6 cars per fifteen minute interval. The probability that less than 10 minutes will elapse between car arrivals is _____________.

a) 0.8465

b) 0.9817

c) 0.0183

d) 0.1535

e) 0.2125

Ans:

Response: See section 6.4, Exponential Distribution

Difficulty: Hard