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.
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.
In this morden time nanotechnology used in many field .
1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc
2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc
3- Atomobile -MEMS, Coating on car etc.
and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change .
maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Source:
OpenStax, Collaborative statistics homework book: custom version modified by r. bloom. OpenStax CNX. Dec 23, 2009 Download for free at http://legacy.cnx.org/content/col10619/1.2
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