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Class Time:


Student learning outcomes:

  • The student will calculate a 90% confidence interval using the given data.
  • The student will determine the relationship between the confidence level and the percent of constructed intervals that contain the population mean.


  1. Heights of 100 women (in inches)
    59.4 71.6 69.3 65.0 62.9
    66.5 61.7 55.2 67.5 67.2
    63.8 62.9 63.0 63.9 68.7
    65.5 61.9 69.6 58.7 63.4
    61.8 60.6 69.8 60.0 64.9
    66.1 66.8 60.6 65.6 63.8
    61.3 59.2 64.1 59.3 64.9
    62.4 63.5 60.9 63.3 66.3
    61.5 64.3 62.9 60.6 63.8
    58.8 64.9 65.7 62.5 70.9
    62.9 63.1 62.2 58.7 64.7
    66.0 60.5 64.7 65.4 60.2
    65.0 64.1 61.1 65.3 64.6
    59.2 61.4 62.0 63.5 61.4
    65.5 62.3 65.5 64.7 58.8
    66.1 64.9 66.9 57.9 69.8
    58.5 63.4 69.2 65.9 62.2
    60.0 58.1 62.5 62.4 59.1
    66.4 61.2 60.4 58.7 66.7
    67.5 63.2 56.6 67.7 62.5
    Listed above are the heights of 100 women. Use a random number generator to randomly select 10 data values.
  2. Calculate the sample mean and sample standard deviation. Assume that the population standard deviation is known to be 3.3 inches. With these values, construct a 90% confidence interval for your sample of10 values. Write the confidence interval you obtained in the first space of the table below.
  3. Now write your confidence interval on the board. As others in the class write their confidence intervals on the board, copy them into the table below:
    90% confidence intervals
    __________ __________ __________ __________ __________
    __________ __________ __________ __________ __________
    __________ __________ __________ __________ __________
    __________ __________ __________ __________ __________
    __________ __________ __________ __________ __________
    __________ __________ __________ __________ __________
    __________ __________ __________ __________ __________
    __________ __________ __________ __________ __________

Discussion questions

  1. The actual population mean for the 100 heights given above is μ = 63 . 4 size 12{μ="63" "." 4} {} . Using the class listing of confidence intervals, count how many of them contain the population mean μ size 12{μ} {} ; i.e., for how many intervals does the value of μ size 12{μ} {} lie between the endpoints of the confidence interval?
  2. Divide this number by the total number of confidence intervals generated by the class to determine the percent of confidence intervals that contains the mean μ size 12{μ} {} . Write this percent below.
  3. Is the percent of confidence intervals that contain the population mean μ size 12{μ} {} close to 90%?
  4. Suppose we had generated 100 confidence intervals. What do you think would happen to the percent of confidence intervals that contained the population mean?
  5. When we construct a 90% confidence interval, we say that we are 90% confident that the true population mean lies within the confidence interval. Using complete sentences, explain what we mean by this phrase.
  6. Some students think that a 90% confidence interval contains 90% of the data. Use the list of data given (the heights of women) and count how many of the data values lie within the confidence interval that you generated on that page. How many of the 100 data values lie within your confidence interval? What percent is this? Is this percent close to 90%?
  7. Explain why it does not make sense to count data values that lie in a confidence interval. Think about the random variable that is being used in the problem.
  8. Suppose you obtained the heights of 10 women and calculated a confidence interval from this information. Without knowing the population mean μ size 12{μ} {} , would you have any way of knowing for certain if your interval actually contained the value of μ size 12{μ} {} ? Explain.
This lab was designed and contributed by Diane Mathios.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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1 It is estimated that 30% of all drivers have some kind of medical aid in South Africa. What is the probability that in a sample of 10 drivers: 3.1.1 Exactly 4 will have a medical aid. (8) 3.1.2 At least 2 will have a medical aid. (8) 3.1.3 More than 9 will have a medical aid.
Nerisha Reply

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