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Three professors at George Washington University did an experiment to determine if economists are more selfish than other people. They dropped 64 stamped, addressed envelopes with $10 cash in different classrooms on the George Washington campus. 44% were returned overall. From the economics classes 56% of the envelopes were returned. From the business, psychology, and history classes 31% were returned. ( Source: Wall Street Journal )

Let: R = money returned; E = economics classes; O = other classes

  • Write a probability statement for the overall percent of money returned.
  • Write a probability statement for the percent of money returned out of the economics classes.
  • Write a probability statement for the percent of money returned out of the other classes.
  • Is money being returned independent of the class? Justify your answer numerically and explain it.
  • Based upon this study, do you think that economists are more selfish than other people? Explain why or why not. Include numbers to justify your answer.
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The chart below gives the number of suicides estimated in the U.S. for a recent year by age, race (black and white), and sex. We are interested in possible relationships between age, race, and sex. We will let suicide victims be our population. ( Source: The National Center for Health Statistics, U.S. Dept. of Health and Human Services )

Race and Sex 1 - 14 15 - 24 25 - 64 over 64 TOTALS
white, male 210 3360 13,610 22,050
white, female 80 580 3380 4930
black, male 10 460 1060 1670
black, female 0 40 270 330
all others
TOTALS 310 4650 18,780 29,760
Do not include "all others" for parts (f), (g), and (i).
  • Fill in the column for the suicides for individuals over age 64.
  • Fill in the row for all other races.
  • Find the probability that a randomly selected individual was a white male.
  • Find the probability that a randomly selected individual was a black female.
  • Find the probability that a randomly selected individual was black
  • Find the probability that a randomly selected individual was male.
  • Out of the individuals over age 64, find the probability that a randomly selected individual was a black or white male.
  • Comparing “Race and Sex” to “Age,” which two groups are mutually exclusive? How do you know?
  • Are being male and committing suicide over age 64 independent events? How do you know?
  • 22050 29760 size 12{ { {"22050"} over {"29760"} } } {}
  • 330 29760 size 12{ { {"330"} over {"29760"} } } {}
  • 2000 29760 size 12{ { { size 8{"2000"} } over { size 8{"29760"} } } } {}
  • 23720 29760 size 12{ { { size 8{"23720"} } over { size 8{"29760"} } } } {}
  • 5010 6020 size 12{ { { size 8{"5010"} } over { size 8{"6020"} } } } {}
  • Black females and ages 1-14
  • No
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The next two questions refer to the following: The percent of licensed U.S. drivers (from a recent year) that are female is 48.60. Of the females, 5.03% are age 19 and under; 81.36% are age 20 - 64; 13.61% are age 65 or over. Of the licensed U.S. male drivers, 5.04% are age 19 and under; 81.43% are age 20 - 64; 13.53% are age 65 or over. (Source: Federal Highway Administration, U.S. Dept. of Transportation)

Complete the following:

  • Construct a table or a tree diagram of the situation.
  • P(driver is female) =
  • P(driver is age 65 or over | driver is female) =
  • P(driver is age 65 or over AND female) =
  • In words, explain the difference between the probabilities in part (c) and part (d).
  • P(driver is age 65 or over) =
  • Are being age 65 or over and being female mutually exclusive events? How do you know
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Questions & Answers

can someone help me with some logarithmic and exponential equations.
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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?
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The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
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Differences Between Laspeyres and Paasche Indices
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No. 7x -4y is simplified from 4x + (3y + 3x) -7y
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. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
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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
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silver nanoparticles could handle the job?
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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.
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1 It is estimated that 30% of all drivers have some kind of medical aid in South Africa. What is the probability that in a sample of 10 drivers: 3.1.1 Exactly 4 will have a medical aid. (8) 3.1.2 At least 2 will have a medical aid. (8) 3.1.3 More than 9 will have a medical aid.
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Source:  OpenStax, Collaborative statistics. OpenStax CNX. Jul 03, 2012 Download for free at http://cnx.org/content/col10522/1.40
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