# 11.7 The chi-square distribution: review  (Page 2/2)

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 $X$ .
• State the distribution for $X$ .
• Find the probability that the emergency room gets no patients with shotgun wounds in the next 28 days.
• $P\left(4\right)$
• 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; $P\left(x=8\right)=0\text{.}\text{0348}$

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.

Becca

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:

Find the number of responses that were “5".

14

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, $\stackrel{̂}{p}$ .
• 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?
• $z=-1\text{.}\text{19}$
• 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.

• $C$ = Californian professional
• $\text{NC}$ = 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?
• $z=2.21$ ; $p=0.0136$
• 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.

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
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
hi
Loga
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!