# 8.1 Homework  (Page 2/5)

 Page 2 / 5

Suppose that a committee is studying whether or not there is waste of time in our judicial system. It is interested in the mean amount of time individuals waste at the courthouse waiting to be called for service. The committee randomly surveyed 81 people. The sample mean was 8 hours with a sample standard deviation of 4 hours.

• $\overline{x}=$ $\text{________}$
• ${s}_{x}=$ $\text{________}$
• $n=$ $\text{________}$
• $n-1=$ $\text{________}$
• Define the Random Variables $X$ and $\overline{X}$ , in words.
• Which distribution should you use for this problem? Explain your choice.
• Construct a 95% confidence interval for the population mean time wasted.
• State the confidence interval.
• Sketch the graph.
• Calculate the error bound.
• Explain in a complete sentence what the confidence interval means.

• 8
• 4
• 81
• 80
• ${t}_{\text{80}}$
• CI: (7.12, 8.88)
• EB = 0.88

Suppose that an accounting firm does a study to determine the time needed to complete one person’s tax forms. It randomly surveys 100 people. The sample mean is 23.6 hours. There is a known standard deviation of 7.0 hours. The population distribution is assumed to be normal.

• $\overline{x}=$ $\text{________}$
• $\sigma =$ $\text{________}$
• ${s}_{x}=$ $\text{________}$
• $n=$ $\text{________}$
• $n-1=$ $\text{________}$
• Define the Random Variables $X$ and $\overline{X}$ , in words.
• Which distribution should you use for this problem? Explain your choice.
• Construct a 90% confidence interval for the population mean time to complete the tax forms.
• State the confidence interval.
• Sketch the graph.
• Calculate the error bound.
• If the firm wished to increase its level of confidence and keep the error bound the same by taking another survey, what changes should it make?
• If the firm did another survey, kept the error bound the same, and only surveyed 49 people, what would happen to the level of confidence? Why?
• Suppose that the firm decided that it needed to be at least 96% confident of the population mean length of time to within 1 hour. How would the number of people the firm surveys change? Why?

A sample of 16 small bags of the same brand of candies was selected. Assume that the population distribution of bag weights is normal. The weight of each bag was then recorded. The mean weight was 2 ounces with a standard deviation of 0.12 ounces. The population standard deviation is known to be 0.1 ounce.

• $\overline{x}=$ $\text{________}$
• $\sigma =$ $\text{________}$
• ${s}_{x}=$ $\text{________}$
• $n=$ $\text{________}$
• $n-1=$ $\text{________}$
• Define the Random Variable $X$ , in words.
• Define the Random Variable $\overline{X}$ , in words.
• Which distribution should you use for this problem? Explain your choice.
• Construct a 90% confidence interval for the population mean weight of the candies.
• State the confidence interval.
• Sketch the graph.
• Calculate the error bound.
• Construct a 98% confidence interval for the population mean weight of the candies.
• State the confidence interval.
• Sketch the graph.
• Calculate the error bound.
• In complete sentences, explain why the confidence interval in (f) is larger than the confidence interval in (e).
• In complete sentences, give an interpretation of what the interval in (f) means.

• 2
• 0.1
• 0.12
• 16
• 15
• the weight of 1 small bag of candies
• the mean weight of 16 small bags of candies
• $N$ $\left(2,\frac{0\text{.}1}{\sqrt{\text{16}}}\right)$
• CI: (1.96, 2.04)
• EB = 0.04
• CI: (1.94, 2.06)
• EB = 0.06

#### 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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