# 4.9 Homework  (Page 2/7)

 Page 2 / 7

## For each problem:

• In words, define the Random Variable $X$ .
• List the values that $X$ may take on.
• Give the distribution of $X$ . $X$ ~
Then, answer the questions specific to each individual problem.

Six different colored dice are rolled. Of interest is the number of dice that show a “1.”

• On average, how many dice would you expect to show a “1”?
• Find the probability that all six dice show a “1.”
• Is it more likely that 3 or that 4 dice will show a “1”? Use numbers to justify your answer numerically.
• $X$ = the number of dice that show a 1
• 0,1,2,3,4,5,6
• $X$ ~ $B\left(6,\frac{1}{6}\right)$
• 1
• 0.00002
• 3 dice

More than 96 percent of the very largest colleges and universities (more than 15,000 total enrollments) have some online offerings. Suppose you randomly pick 13 such institutions. We are interested in the number that offer distance learning courses. (Source: http://en.wikipedia.org/wiki/Distance_education)

• On average, how many schools would you expect to offer such courses?
• Find the probability that at most 6 offer such courses.
• Is it more likely that 0 or that 13 will offer such courses? Use numbers to justify your answer numerically and answer in a complete sentence.

A school newspaper reporter decides to randomly survey 12 students to see if they will attend Tet (Vietnamese New Year) festivities this year. Based on past years, she knows that 18% of students attend Tet festivities. We are interested in the number of students who will attend the festivities.

• How many of the 12 students do we expect to attend the festivities?
• Find the probability that at most 4 students will attend.
• Find the probability that more than 2 students will attend.
• $X$ = the number of students that will attend Tet.
• 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
• $X$ ~ $\text{B(12,0.18)}$
• 2.16
• 0.9511
• 0.3702

Suppose that about 85% of graduating students attend their graduation. A group of 22 graduating students is randomly chosen.

• How many are expected to attend their graduation?
• Find the probability that 17 or 18 attend.
• Based on numerical values, would you be surprised if all 22 attended graduation? Justify your answer numerically.

At The Fencing Center, 60% of the fencers use the foil as their main weapon. We randomly survey 25 fencers at The Fencing Center. We are interested in the numbers that do not use the foil as their main weapon.

• How many are expected to not use the foil as their main weapon?
• Find the probability that six do not use the foil as their main weapon.
• Based on numerical values, would you be surprised if all 25 did not use foil as their main weapon? Justify your answer numerically.
• $X$ = the number of fencers that do not use foil as their main weapon
• 0, 1, 2, 3,... 25
• $X$ ~ $\text{B(25,0.40)}$
• 10
• 0.0442
• Yes

Approximately 8% of students at a local high school participate in after-school sports all four years of high school. A group of 60 seniors is randomly chosen. Of interest is the number that participated in after-school sports all four years of high school.

• How many seniors are expected to have participated in after-school sports all four years of high school?
• Based on numerical values, would you be surprised if none of the seniors participated in after-school sports all four years of high school? Justify your answer numerically.
• Based upon numerical values, is it more likely that 4 or that 5 of the seniors participated in after-school sports all four years of high school? Justify your answer numerically.

#### Questions & Answers

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
characteristics of micro business
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
what is biological synthesis of nanoparticles
how did you get the value of 2000N.What calculations are needed to arrive at it
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