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 Collaborative statistics homework
 Discrete random variables
 Homework (modified r. bloom)
For each problem:

A
In words, define the Random Variable
$X$ .

B
List the values hat
$X$ may take on.

C
Give the distribution of
$X$ .
$X$ ~
Then, answer the questions specific to each individual problem.
Six different colored dice are rolled. Of interest is the number of dice that show a “1.”

D
On average, how many dice would you expect to show a “1”?

E
Find the probability that all six dice show a “1.”

F
Is it more likely that 3 or that 4 dice will show a “1”? Use numbers to justify your answer numerically.

A
$X$ = the number of dice that show a 1

B
0,1,2,3,4,5,6

C
$X$ ~
$B(6,\frac{1}{6})$

D
1

E
0.00002

F
3 dice
According to a 2003 publication by Waits and Lewis
(source:
http://nces.ed.gov/pubs2003/2003017.pdf
), by the end of 2002, 92% of U.S. public twoyear colleges offered distance learning courses. Suppose you randomly pick 13 U.S. public twoyear colleges. We are interested in the number that offer distance learning courses.

D
On average, how many schools would you expect to offer such courses?

E
Find the probability that at most 6 offer such courses.

F
Is it more likely that 0 or that 13 will offer such courses? Use numbers to justify your answer numerically and answer in a complete sentence.
A school newspaper reporter decides to randomly survey 12 students to see if they will attend Tet festivities this year. Based on past years, she knows that 18% of students attend Tet festivities. We are interested in the number of students who will attend the festivities.

D
How many of the 12 students do we expect to attend the festivities?

E
Find the probability that at most 4 students will attend.

F
Find the probability that more than 2 students will attend.

A
$X$ = the number of students that will attend Tet.

B
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

C
$X$ ~
$\text{B(12,0.18)}$

D
2.16

E
0.9511

F
0.3702
Suppose that about 85% of graduating students attend their graduation. A group of 22 graduating students is randomly chosen.

D
How many are expected to attend their graduation?

E
Find the probability that 17 or 18 attend.

F
Based on numerical values, would you be surprised if all 22 attended graduation? Justify your answer numerically.
At The Fencing Center, 60% of the fencers use the foil as their main weapon. We randomly survey 25 fencers at The Fencing Center. We are interested in the numbers that do
not use the foil as their main weapon.

D
How many are expected to
not use the foil as their main weapon?

E
Find the probability that six do
not use the foil as their main weapon.

F
Based on numerical values, would you be surprised if all 25 did
not use foil as their main weapon? Justify your answer numerically.

A
$X$ = the number of fencers that do
not use foil as their main weapon

B
0, 1, 2, 3,... 25

C
$X$ ~
$\text{B(25,0.40)}$

D
10

E
0.0442

F
Yes
Approximately 8% of students at a local high school participate in afterschool sports all four years of high school. A group of 60 seniors is randomly chosen. Of interest is the number that participated in afterschool sports all four years of high school.

D
How many seniors are expected to have participated in afterschool sports all four years of high school?

E
Based on numerical values, would you be surprised if none of the seniors participated in afterschool sports all four years of high school? Justify your answer numerically.

F
Based upon numerical values, is it more likely that 4 or that 5 of the seniors participated in afterschool sports all four years of high school? Justify your answer numerically.
Questions & Answers
why our wants are limited
nooo want is unlimited
but resources are limited
Ruchi
and do to that there occurs scarcity and we have to make choice in order to have what we need if need be I will explain more
Madara
our wants are not limited but rather the resources
Moses
as we know that
there are two principle of microeconomics
scarcity of resources
and they have alternative uses...
Ruchi
demand is something wt we called in economic theory of demand
it simply means if price of product is increase then demand of product will decrease
Ruchi
inverse relationship between demand and price
Ruchi
demand is what and how much you want and what's your need...
Shikhar
how can one be so with economics even while you have less knowledge in mathematics.
why is it that some products increases everyday by day
because demand is increase
Ruchi
because demand is increase
Patience
but how demand increases?
Aziz
Because of the Marketing and purchasing power of people.
AmarbirSingh
but how could we know that people's demands have increased everyday by day and how could we know that this is time to produced the products in the market. Is any connection among them
yaqoob
for normal good people demand remain the same if price of product will increase or not
Ruchi
see that some product which increases day by day
is comes under normal good which is used by consumer
Ruchi
Seems hot discussing going here
Shamamet
If there are less products demand starts to increase for those products
Shamamet
Economics is really interesting to learn ....
Shamamet
see there is Inferior goods ands normal goods
inferior good demand is rarely increase whereas as we talk about normal good demand will absolutely Increase whether price is increase or not
Ruchi
and demand for normal goods increase cause people's income as a while increases time to time
Abhisek
and it might also be that the cost of raw materials are high.
ATTAH
obviously because demand is increasing.....and price is getting low.....
Shikhar
hmmm there is inverse relationship between demand and price
Ruchi
the nature and significance of economics studies
Deborah
deman is amount of goods and services a consumer is willing and able to buy or purchase at a given price.
Sainabou
the willingness and ability of a body to purchase goods nd servicesbis called demand ,so if she/has ability but doesn't have willingness it's not a demand same if she or he has willingness but doesn't has ability it's not a demand too
Gul
Demand refers to as quantities of a goods and services in which consumers are willing and able to purchase at a given period of time and demand can also be defined as the desire or willingness and backed by the ability to pay.
Fadiga
Choice refers to the ability of a consumer or producer to decide which good, service or resource to purchase or provide from a range of possible options. Being free to chose is regarded as a fundamental indicator of economic well being and development.
Shonal
choice is a act of selecting or choosing from the numerous or plenty wants.
Fadiga
how does consumer make profit
Compare and contract the function of commercial bank and the central bank of Nigeria
what do think is the difference between overhead costs and prime cost
Abdoulkarim
economics is a social science that study's how resources can be used to produce goods and services for society
Nathan
Economic is a science which studies human behavior as a relationship between ends and scares means which have alternatives uses or purposes.
Fadiga
what is the basic economic problem
unlimited wants vs limited resources
Nathan
what economics is all about?
what is a new paradigm shift
Paradigm shift it is the reconcilliation of fedural goods in production
Shyline
fedural? what is that?
Aziz
factors that affecting economic system
While the American heart association suggests that meditation might be used in conjunction with more traditional treatments as a way to manage hypertension
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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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