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This module provides a number of homework/review exercises summarizing topics related to Discrete Random Variables.

A sociologist wants to know the opinions of employed adult women about government funding for day care. She obtains a list of 520 members of a local business and professional women’s club and mails a questionnaire to 100 of these women selected at random. 68 questionnaires are returned. What is the population in this study?

  • All employed adult women
  • All the members of a local business and professional women’s club
  • The 100 women who received the questionnaire
  • All employed women with children

A

The next two questions refer to the following: An article from The San Jose Mercury News was concerned with the racial mix of the 1500 students at Prospect High School in Saratoga, CA. The table summarizes the results. (Male and female values are approximate.)

Ethnic Group
Gender White Asian Hispanic Black American Indian
Male 400 168 115 35 16
Female 440 132 140 40 14

Find the probability that a student is Asian or Male.

0.5773

Find the probability that a student is Black given that the student is Female.

0.0522

A sample of pounds lost, in a certain month, by individual members of a weight reducing clinic produced the following statistics:

  • Mean = 5 lbs.
  • Median = 4.5 lbs.
  • Mode = 4 lbs.
  • Standard deviation = 3.8 lbs.
  • First quartile = 2 lbs.
  • Third quartile = 8.5 lbs.

The correct statement is:

  • One fourth of the members lost exactly 2 pounds.
  • The middle fifty percent of the members lost from 2 to 8.5 lbs.
  • Most people lost 3.5 to 4.5 lbs.
  • All of the choices above are correct.

B

What does it mean when a data set has a standard deviation equal to zero?

  • All values of the data appear with the same frequency.
  • The mean of the data is also zero.
  • All of the data have the same value.
  • There are no data to begin with.

C

The statement that best describes the illustration below is:

Horizontal boxplot starting with a dashed line and ending with one whisker on the right.

  • The mean is equal to the median.
  • There is no first quartile.
  • The lowest data value is the median.
  • The median equals ( Q1 + Q3 ) 2 size 12{ { { size 8{ \( Q1+Q3 \) } } over { size 8{2} } } } {}

C

A “friend” offers you the following “deal.” For a $10 fee, you may pick an envelope from a box containing 100 seemingly identical envelopes. However, each envelope contains a coupon for a free gift.

  • 10 of the coupons are for a free gift worth $6.
  • 80 of the coupons are for a free gift worth $8.
  • 6 of the coupons are for a free gift worth $12.
  • 4 of the coupons are for a free gift worth $40.

Based upon the financial gain or loss over the long run, should you play the game?

  • Yes, I expect to come out ahead in money.
  • No, I expect to come out behind in money.
  • It doesn’t matter. I expect to break even.

B

The next four questions refer to the following: Recently, a nurse commented that when a patient calls the medical advice line claiming to have the flu , the chance that he/she truly has the flu (and not just a nasty cold) is only about 4%. Of the next 25 patients calling in claiming to have the flu , we are interested in how many actually have the flu .

Define the Random Variable and list its possible values.

X size 12{X} {} = the number of patients calling in claiming to have the flu , who actually have the flu . X size 12{X} {} = 0, 1, 2, ...25

State the distribution of X size 12{X} {} .

B ( 25 , 0 . 04 ) size 12{B \( "25",0 "." "04" \) } {}

Find the probability that at least 4 of the 25 patients actually have the flu .

0.0165

On average, for every 25 patients calling in, how many do you expect to have the flu ?

1

The next two questions refer to the following: Different types of writing can sometimes be distinguished by the number of letters in the words used. A student interested in this fact wants to study the number of letters of words used by Tom Clancy in his novels. She opens a Clancy novel at random and records the number of letters of the first 250 words on the page.

What kind of data was collected?

  • qualitative
  • quantitative - continuous
  • quantitative – discrete

C

What is the population under study?

All words used by Tom Clancy in his novels

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
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
Brian Reply
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?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
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 ?
Bob Reply
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?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
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?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
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
Smarajit Reply
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Good
Berger describes sociologists as concerned with
Mueller Reply
what is hormones?
Wellington
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Source:  OpenStax, Elementary statistics. OpenStax CNX. Dec 30, 2013 Download for free at http://cnx.org/content/col10966/1.4
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