Bus224

Exam-2

Total Points:
100

1.
The file name Exam-2, sheet named Part 1
is kept blank. Use Part 1 sheet to
answer this question. Put a box around your answer. Round your answers to 4
decimal places.

Ship collisions in the Houston Ship Channel are
rare. Suppose the number of collisions are Poisson distributed, with a mean of
1.2 collisions every four months. What is the probability of having less than
two collisions over a four-month period?

[10 points]

2.
The file name Exam-2, sheet named Part 2
is kept blank. Use Part 2 sheet to
answer this question. Put a box around your answers. For (a) and (b), round
your answers to 4 decimal places.

A survey conducted for the Northwestern National
Life Insurance Company revealed that 70% of American workers say job stress
caused frequent health problems. Suppose a random sample of 10 American workers
is selected.

a) What
is the probability that more than seven of them say job stress caused frequent
health problems?

b) What
is the probability that exactly five say job stress caused frequent health
problems?

c) What
is the expected [mean] number of workers that would say job stress caused
frequent health problems?

[Hint: Use binomial
distribution to answer question 2]

[10 + 5 + 5 = 20
points]

3. The file name Exam-2, sheet named Part 3
is kept blank. Use Part 3 sheet to
answer this question. Put a box around your answer. Round your answer to 1
decimal places.

The U.S. national average door-to-doctor wait time
for patients to see a doctor is now 21.3 minutes. Suppose such wait times are
normally distributed with a standard deviation of 6.7 minutes. Some patients
will have to wait much longer than the mean to see the doctor. In fact, based
on this information, 3% of patients still have to wait more than how many
minutes to see a doctor?

[15 points]

4.
The file name Exam-2, sheet named Part 4
is kept blank. Use Part 4 sheet to
answer this question. Put a box around your answers. Round your answers to 4
decimal places.

According to CBS Money Watch, the
average monthly household cellular phone bill is $100. Suppose monthly
household cell phone bills are normally distributed with a standard deviation
of $11.35.

a)
What is the probability that a
randomly selected monthly cell phone bill is less than $127?

b)
What is the probability that a
randomly selected monthly cell phone bill is more than $125?

c)
What is the probability that a
randomly selected monthly cell phone bill is between $87 and $110?

d)
What is the probability that a randomly
selected monthly cell phone bill is no more than $82?

[5 + 7.5+ 12.5 + 5 = 30 points]

5.
Use Part 5 sheet to answer this question. Put a box around your answers.

A bicycle company makes two mountain
bike models that each come in three colors. The following table shows the
production volumes for last week:

Color |
|||

Model |
Blue |
Brown |
White |

XB-50 |
288 |
93 |
210 |

FL-99 |
32 |
220 |
128 |

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