# 5.9 Review

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This module provides a number of homework/review exercises summarizing topics related to Discrete Random Variables.

A sociologist wants to know the opinions of employed adult women about government funding for day care. She obtains a list of 520 members of a local business and professional women’s club and mails a questionnaire to 100 of these women selected at random. 68 questionnaires are returned. What is the population in this study?

• All the members of a local business and professional women’s club
• The 100 women who received the questionnaire
• All employed women with children

A

The next two questions refer to the following: An article from The San Jose Mercury News was concerned with the racial mix of the 1500 students at Prospect High School in Saratoga, CA. The table summarizes the results. (Male and female values are approximate.)

Ethnic Group
Gender White Asian Hispanic Black American Indian
Male 400 168 115 35 16
Female 440 132 140 40 14

Find the probability that a student is Asian or Male.

0.5773

Find the probability that a student is Black given that the student is Female.

0.0522

A sample of pounds lost, in a certain month, by individual members of a weight reducing clinic produced the following statistics:

• Mean = 5 lbs.
• Median = 4.5 lbs.
• Mode = 4 lbs.
• Standard deviation = 3.8 lbs.
• First quartile = 2 lbs.
• Third quartile = 8.5 lbs.

The correct statement is:

• One fourth of the members lost exactly 2 pounds.
• The middle fifty percent of the members lost from 2 to 8.5 lbs.
• Most people lost 3.5 to 4.5 lbs.
• All of the choices above are correct.

B

What does it mean when a data set has a standard deviation equal to zero?

• All values of the data appear with the same frequency.
• The mean of the data is also zero.
• All of the data have the same value.
• There are no data to begin with.

C

The statement that best describes the illustration below is:

• The mean is equal to the median.
• There is no first quartile.
• The lowest data value is the median.
• The median equals $\frac{\left(\mathrm{Q1}+\mathrm{Q3}\right)}{2}$

C

A “friend” offers you the following “deal.” For a $10 fee, you may pick an envelope from a box containing 100 seemingly identical envelopes. However, each envelope contains a coupon for a free gift. • 10 of the coupons are for a free gift worth$6.
• 80 of the coupons are for a free gift worth $8. • 6 of the coupons are for a free gift worth$12.
• 4 of the coupons are for a free gift worth \$40.

Based upon the financial gain or loss over the long run, should you play the game?

• Yes, I expect to come out ahead in money.
• No, I expect to come out behind in money.
• It doesn’t matter. I expect to break even.

B

The next four questions refer to the following: Recently, a nurse commented that when a patient calls the medical advice line claiming to have the flu , the chance that he/she truly has the flu (and not just a nasty cold) is only about 4%. Of the next 25 patients calling in claiming to have the flu , we are interested in how many actually have the flu .

Define the Random Variable and list its possible values.

$X$ = the number of patients calling in claiming to have the flu , who actually have the flu . $X$ = 0, 1, 2, ...25

State the distribution of $X$ .

$B\left(\text{25},0\text{.}\text{04}\right)$

Find the probability that at least 4 of the 25 patients actually have the flu .

0.0165

On average, for every 25 patients calling in, how many do you expect to have the flu ?

1

The next two questions refer to the following: Different types of writing can sometimes be distinguished by the number of letters in the words used. A student interested in this fact wants to study the number of letters of words used by Tom Clancy in his novels. She opens a Clancy novel at random and records the number of letters of the first 250 words on the page.

What kind of data was collected?

• qualitative
• quantitative - continuous
• quantitative – discrete

C

What is the population under study?

All words used by Tom Clancy in his novels

what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
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