117.
What is the probability that a randomly selected cable repair visit falls within 2
standard deviations of the mean?
=
Difficulty: Hard

Use the following information to answer questions 118-122:
Suppose that the waiting time for a license plate renewal at a local office of a state motor
vehicle department has been found to be normally distributed
with a mean of 30 minutes
and a standard deviation of 8 minutes. What is the probability that a randomly selected
individual will have a waiting time:
118.
Between 15 and 45 minutes

Difficulty: Medium
119.
At least 10 minutes

##### We have textbook solutions for you!

**The document you are viewing contains questions related to this textbook.**

**The document you are viewing contains questions related to this textbook.**

Expert Verified

Answer: .1587

P(x≤22) =
Difficulty: Hard
121.
Suppose that in an effort to provide better service to the public, the director of the
local office is permitted to provide discounts to those individuals whose waiting time
exceeds a predetermined time.
The director decides that 15% of the customers should
receive this discount.
What are the number of minutes they need to wait to receive the
discount?
Difficulty: Hard

122.
Complete the following statement:
Only 20% of the individuals wait less than
_____ minutes.

Difficulty: Hard
Use the following information to answer questions 123-127:
A set of final examination grades in a calculus course was found to be normally
distributed with a mean of 69 and a standard deviation of 9.
123.
What is the probability of getting a grade of 91 or less on this exam?

Difficulty: Hard
124.
What percentage of students scored between 65 and 89?

Difficulty: Medium

125.
What percentage of students scored between 81 and 89?

.4868-.4332=.0536
Difficulty: Medium
126.
Only 5% of the students taking the test scored higher than what grade?
Difficulty: Hard

127.
A manufacturer of personal computers sets tests competing brands and finds that the
amounts of energy they require are normally distributed with a mean of 285 kwh and a
standard deviation of 9.1 kwh.
If the lowest 25% and the highest 30% are not included in a second round of tests, what
are the upper and lower limits for the energy amounts of the remaining sets?
Difficulty: Hard

Use the following information to answer questions 128-132:
While conducting experiments, a marine biologist selects water depths from a uniformly
distributed collection that vary between 2.00 m and 7.00 m.
128.
What is the probability that a randomly selected depth is less than 3.60 m?
Difficulty: Easy