# STAT 200 QZ 2

1.

(3

points) Of the Statistics graduates of a University 40%, received a starting

salary of $45,000.00. If 5 of them are randomly selected, find the probability

that all the graduated STUDENTS had starting salary of $40,000.00.

2.

(3

points) A Physics test consists of 40 true/false questions. Find that how many

different possible answer keys can be made.

3.

(3

points) Most of us love Philippine mangoes, but hate buying those that are

picked too early. Unfortunately, by waiting until the mangos are almost ripe to

pick carries a risk of having 15% of the picked rot upon arrival at the packing

facility. If the packing process is all done by machines without human

inspection to pick out any rotten mangos, what would be the probability of

having at most 2 rotten mangos packed in a box of 12?

4.

(3)

Average person who drives car in United States drives 12, 400 which is 50% more

than an average driver in Europe. We assume that the number of yearly miles by

U.S. drivers is approximately a normal random variable of standard deviation of

3800 miles. Calculate percent of drivers who traveled between 10,000 to 15,000

miles in a year.

5.

(3

points) A soda company want to stimulate sales in this economic climate by

giving customers a chance to win a small prize for ever bottle of soda they

buy. There is a 20% chance that a customer will find a picture of a dancing

banana at the bottom of the cap upon opening up a bottle of soda. The customer

can then redeem that bottle cap with this picture for a small prize. Now, if I

buy a 6-pack of soda, what is the probability that I will win something, i.e.,

at least win a single small prize?

6.

(2

points) At men’s clothing store, 14 males bought green sweaters, 8 purchased

blue golf sweaters, 5 bought white sweaters and 9 decided to by grayish-yellow

sweaters. If a customer is selected at random, calculate the probability that

he bought:

(a)

Green

sweater

(b)

blue sweater or white

(c) blue or gray or white

(d)

A sweater which was not gray.

*Important:*

Please read carefully....... You are allowed to use technology for the

following Problems (Problem #7 and Problem #8), and these two Problems only.

Most probably, you have to use technology or you may have to spend hours, to

carry out the necessary calculations by hand. Nonetheless, you should clearly

delineate and explain your logic and reasoning on how to tackle these two

problems.Please read carefully....... You are allowed to use technology for the

following Problems (Problem #7 and Problem #8), and these two Problems only.

Most probably, you have to use technology or you may have to spend hours, to

carry out the necessary calculations by hand. Nonetheless, you should clearly

delineate and explain your logic and reasoning on how to tackle these two

problems.

7. (6 points) The Undesirable Air

Lines (UAL???) is notorious for its cost-cutting substandard customer service. Consequently,

only 85% of the ticket holders will show up for a flight. The Air Lines

workhorse, the Boring 878, has 234 seats. UAL, of course, will make extra money

by overbooking. However, they have to worry about the FAA fines, and they have

to keep a safety margin, say, that there is at least 95% probability that they

can accommodate all those who show up for the Boring 878 flight. How many seats

can they actually sell in this case?

8. (7 points) It is an open

secret that airlines overbook flights, but I have just learned recently that

bookstores

**underbook**

(I

might have invented this new term.) textbooks..........

To make a long story short, our

UMUC designated virtual bookstore, MBS Direct, routinely, as a matter of

business practice, orders less textbooks than the amount requested by UMUC's

Registrar's Office. That is what I have figured out....... Simply put, MBS

Direct has to "eat" the books if they are not sold. Do you want to

eat the books? You may want to cook the books before you eat them! Oops, I hope

there is no account major in this class?

OK, let us cut to the chase.....

MBS Direct believes that only 85% of our registered students will stay

registered in a class long enough to purchase the required textbook. Let's pick

on our STAT 200 students. According to the Registrar's Office, we have 600

students enrolled in STAT 200 this spring 2014.

Suppose you are the CEO of MBS

Direct, and you want to perform a probability analysis. What would be the

number of STAT 200 textbook bundles you would order so that you stay below 5%

probability of having to back-order from Pearson Custom Publishing? (

*Note: Our Provost would be*

very angry when she hears that textbook bundles have to be back-ordered.In any case, by

very angry when she hears that textbook bundles have to be back-ordered.

next fall, we will no longer need the service of MBS Direct as we are moving

100% to free eResources.

*Auf Wiedersehen*, MBS Direct......)

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