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The next three problems refer to the following situation: Suppose that a sample of 15 randomly chosen people were put on a special weight loss diet. The amount of weight lost, in pounds, follows an unknown distribution with mean equal to 12 pounds and standard deviation equal to 3 pounds. Assume that the distribution for the weight loss is normal.

To find the probability that the mean amount of weight lost by 15 people is no more than 14 pounds, the random variable should be:

  • The number of people who lost weight on the special weight loss diet
  • The number of people who were on the diet
  • The mean amount of weight lost by 15 people on the special weight loss diet
  • The total amount of weight lost by 15 people on the special weight loss diet


Find the probability asked for in the previous problem.


Find the 90th percentile for the mean amount of weight lost by 15 people.


The next three questions refer to the following situation: The time of occurrence of the first accident during rush-hour traffic at a major intersection is uniformly distributed between the three hour interval 4 p.m. to 7 p.m. Let X size 12{X} {} = the amount of time (hours) it takes for the first accident to occur.

  • So, if an accident occurs at 4 p.m., the amount of time, in hours, it took for the accident to occur is _______.
  • μ = size 12{μ} {} _______
  • σ 2 = size 12{σ rSup { size 8{2} } } {} _______

What is the probability that the time of occurrence is within the first half-hour or the last hour of the period from 4 to 7 p.m.?

  • Cannot be determined from the information given
  • 1 6 size 12{ { { size 8{1} } over { size 8{6} } } } {}
  • 1 2 size 12{ { { size 8{1} } over { size 8{2} } } } {}
  • 1 3 size 12{ { { size 8{1} } over { size 8{3} } } } {}


The 20th percentile occurs after how many hours?

  • 0.20
  • 0.60
  • 0.50
  • 1


Assume Ramon has kept track of the times for the first accidents to occur for 40 different days. Let C size 12{C} {} = the total cumulative time. Then C size 12{C} {} follows which distribution?

  • U ( 0,3 ) size 12{U \( 0,3 \) } {}
  • Exp ( 1 3 ) size 12{ ital "Exp" \( { { size 8{1} } over { size 8{3} } } \) } {}
  • N ( 60 , 5.477 ) size 12{N \( "60","30" \) } {}
  • N ( 1 . 5,0 . 01875 ) size 12{N \( 1 "." 5,0 "." "01875" \) } {}


Using the information in question #6, find the probability that the total time for all first accidents to occur is more than 43 hours.


The next two questions refer to the following situation: The length of time a parent must wait for his children to clean their rooms is uniformly distributed in the time interval from 1 to 15 days.

How long must a parent expect to wait for his children to clean their rooms?

  • 8 days
  • 3 days
  • 14 days
  • 6 days


What is the probability that a parent will wait more than 6 days given that the parent has already waited more than 3 days?

  • 0.5174
  • 0.0174
  • 0.7500
  • 0.2143


The next five problems refer to the following study: Twenty percent of the students at a local community college live in within five miles of the campus. Thirty percent of the students at the same community college receive some kind of financial aid. Of those who live within five miles of the campus, 75% receive some kind of financial aid.

Find the probability that a randomly chosen student at the local community college does not live within five miles of the campus.

  • 80%
  • 20%
  • 30%
  • Cannot be determined


Find the probability that a randomly chosen student at the local community college lives within five miles of the campus or receives some kind of financial aid.

  • 50%
  • 35%
  • 27.5%
  • 75%


Based upon the above information, are living in student housing within five miles of the campus and receiving some kind of financial aid mutually exclusive?

  • Yes
  • No
  • Cannot be determined


The interest rate charged on the financial aid is _______ data.

  • quantitative discrete
  • quantitative continuous
  • qualitative discrete
  • qualitative


What follows is information about the students who receive financial aid at the local community college.

  • 1st quartile = $250
  • 2nd quartile = $700
  • 3rd quartile = $1200

(These amounts are for the school year.) If a sample of 200 students is taken, how many are expected to receive $250 or more?

  • 50
  • 250
  • 150
  • Cannot be determined

  • 150

The next two problems refer to the following information: P ( A ) = 0 . 2 size 12{P \( A \) =0 "." 2} {} , P ( B ) = 0 . 3 size 12{P \( B \) =0 "." 3} {} , A size 12{A} {} and B size 12{B} {} are independent events.

P ( A AND B ) = size 12{P \( A} {}

  • 0.5
  • 0.6
  • 0
  • 0.06


P ( A OR B ) = size 12{P \( A} {}

  • 0.56
  • 0.5
  • 0.44
  • 1


If H size 12{H} {} and D size 12{D} {} are mutually exclusive events, {} P ( H ) = 0 . 25 size 12{P \( H \) =0 "." "25"} {} , P ( D ) = 0 . 15 size 12{P \( D \) =0 "." "15"} {} , then P ( H | D ) size 12{P \( H} {}

  • 1
  • 0
  • 0.40
  • 0.0375


Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
I'm not good at math so would you help me
what is the problem that i will help you to self with?
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele 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 (with edits: teegarden). OpenStax CNX. Jul 20, 2009 Download for free at http://legacy.cnx.org/content/col10561/1.3
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