# 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.

anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
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
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
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
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