Question 3 of 20
1.0/ 1.0 Points

Feedback: In Excel,
=1-NORM.S.DIST(1.8,TRUE)
Part 2 of 6 - Continuous Random Variables and Probability Functions Questions
1.0/ 1.0 Points
Question 4 of 20
1.0/ 1.0 Points
Find the probability that
falls in the shaded area.

A.
0.125
B.
0.50
C.
0.438

Feedback: (1/30)(16 - 4)
Part 3 of 6 - The Central Limit Theorem Questions
1.0/ 1.0 Points
Question 5 of 20
1.0/ 1.0 Points
The cost of unleaded gasoline in the Bay Area once followed a normal distribution with a mean
of $4.59 and a standard deviation of $0.10. Sixteen gas stations from the Bay area are randomly
chosen. We are interested in the average cost of gasoline for the 30 gas stations. Find the exact
probability that the average price for 30 gas stations is less than $4.55.

D.
0.3446
Answer Key: C
Feedback:
New SD = .10/SQRT(30) = 0.018257419
P(x < 4.55) In Excel, =NORM.DIST(4.55,4.59,0.018257,TRUE)
Part 4 of 6 - The Exponential Distribution Questions
4.0/ 4.0 Points
Question 6 of 20
1.0/ 1.0 Points
The life of an electric component has an exponential distribution with a mean of 8 years. What is
the probability that a randomly selected one such component has a life less than 5 years?

Question 7 of 20
1.0/ 1.0 Points
The caller times at a customer service center has an exponential distribution with an average of
10 seconds. Find the probability that a randomly selected call time will be less than 25 seconds?

Feedback:
P(x < 25)
In Excel,
=EXPON.DIST(25,1/10,TRUE)
Question 8 of 20
1.0/ 1.0 Points
Suppose that the longevity of a light bulb is exponential with a mean lifetime of eight years.
Find the probability that a light bulb lasts between six and ten years.

E.
0.3682
Answer Key: B
Feedback:
P( 6 < x < 10)
P(x < 10) - P( x < 6)
In Excel,
=EXPON.DIST(10,1/8,TRUE)-EXPON.DIST(6,1/8,TRUE)
Question 9 of 20
1.0/ 1.0 Points
The average lifetime of a set of tires is three years. The manufacturer will replace any set of tires
failing within two years of the date of purchase. The lifetime of these tires is known to follow an
exponential distribution. What is the probability that the tires will fail within two years of the
date of purchase?

C.
0.4866
D.
0.9997
Answer Key: C
Feedback:
P(x < 2)
In Excel,
=EXPON.DIST(2,1/3,TRUE)
Part 5 of 6 - The Uniform Distribution Questions
6.0/ 6.0 Points
Question 10 of 20
1.0/ 1.0 Points
A local pizza restaurant delivery time has a uniform distribution over 0 to 60 minutes. What is
the probability that the pizza delivery time is more than 25 minutes on a given day? Answer:
(Round to 2 decimal places.) 0.58

P(x > 25) =