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What type of data is the number of 20 year olds considered to be?

quantitative - discrete

On average, a busy emergency room gets a patient with a shotgun wound about once per week. We are interested in the number of patients with a shotgun wound the emergency room gets per 28 days.

  • Define the random variable X size 12{X} {} .
  • State the distribution for X size 12{X} {} .
  • Find the probability that the emergency room gets no patients with shotgun wounds in the next 28 days.
  • P 4 size 12{P left (4 right )} {}
  • 0.0183

The next two questions refer to the following information:

The probability that a certain slot machine will pay back money when a quarter is inserted is 0.30 . Assume that each play of the slot machine is independent from each other. A person puts in 15 quarters for 15 plays.

Is the expected number of plays of the slot machine that will pay back money greater than, less than or the same as the median? Explain your answer.

greater than

Is it likely that exactly 8 of the 15 plays would pay back money? Justify your answer numerically.

No; P x = 8 = 0 . 0348 size 12{P left (x=8 right )=0 "." "0348"} {}

A game is played with the following rules:

  • it costs $10 to enter
  • a fair coin is tossed 4 times
  • if you do not get 4 heads or 4 tails, you lose your $10
  • if you get 4 heads or 4 tails, you get back your $10, plus $30 more

Over the long run of playing this game, what are your expected earnings?

You will lose $5

  • The mean grade on a math exam in Rachel’s class was 74, with a standard deviation of 5. Rachel earned an 80.
  • The mean grade on a math exam in Becca’s class was 47, with a standard deviation of 2. Becca earned a 51.
  • The mean grade on a math exam in Matt’s class was 70, with a standard deviation of 8. Matt earned an 83.

Find whose score was the best, compared to his or her own class. Justify your answer numerically.


The next two questions refer to the following information:

A random sample of 70 compulsive gamblers were asked the number of days they go to casinos per week. The results are given in the following graph:

Histogram of 5 bars with relative frequency on the y-axis, from 0.1-0.3 in increments of 0.1, and number of days on the x-axis, from 0-7 in increments of 1. No bars are present for 4 or 6.

Find the number of responses that were “5".


Find the mean, standard deviation, the median, the first quartile, the third quartile and the IQR.

  • Sample mean = 3.2
  • Sample standard deviation = 1.85
  • Median = 3
  • Quartile 1 = 2
  • Quartile 3 = 5
  • IQR = 3

Based upon research at De Anza College, it is believed that about 19% of the student population speaks a language other than English at home.

Suppose that a study was done this year to see if that percent has decreased. Ninety-eight students were randomly surveyed with the following results. Fourteen said that they speak a language other than English at home.

  • State an appropriate null hypothesis.
  • State an appropriate alternate hypothesis.
  • Define the Random Variable, p ̂ size 12{P'} {} .
  • Calculate the test statistic.
  • Calculate the p-value.
  • At the 5% level of decision, what is your decision about the null hypothesis?
  • What is the Type I error?
  • What is the Type II error?
  • z = 1 . 19 size 12{z= - 1 "." "19"} {}
  • 0.1171
  • Do not reject the null

Assume that you are an emergency paramedic called in to rescue victims of an accident. You need to help a patient who is bleeding profusely. The patient is also considered to be a high risk for contracting AIDS. Assume that the null hypothesis is that the patient does not have the HIV virus. What is a Type I error?

We conclude that the patient does have the HIV virus when, in fact, the patient does not.

It is often said that Californians are more casual than the rest of Americans. Suppose that a survey was done to see if the proportion of Californian professionals that wear jeans to work is greater than the proportion of non-Californian professionals. Fifty of each was surveyed with the following results. 15 Californians wear jeans to work and 6 non-Californians wear jeans to work.

  • C size 12{C} {} = Californian professional
  • NC size 12{ ital "NC"} {} = non-Californian professional
  • State appropriate null and alternate hypotheses.
  • Define the Random Variable.
  • Calculate the test statistic and p-value.
  • At the 5% significance level, what is your decision?
  • What is the Type I error?
  • What is the Type II error?
  • z = 2.21 size 12{z=1 "." "73"} {} ; p = 0.0136 size 12{p=0 "." "0419"} {}
  • Reject the null
  • We conclude that the proportion of Californian professionals that wear jeans to work is greater than the proportion of non-Californian professionals when, in fact, it is not greater.
  • We cannot conclude that the proportion of Californian professionals that wear jeans to work is greater than the proportion of non-Californian professionals when, in fact, it is greater.

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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Source:  OpenStax, Collaborative statistics using spreadsheets. OpenStax CNX. Jan 05, 2016 Download for free at http://legacy.cnx.org/content/col11521/1.23
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