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This module provides a number of homework/review problems related to Continuous Random Variables.

[link][link] refer to the following study: A recent study of mothers of junior high school children in Santa Clara County reported that 76% of the mothers are employed in paid positions. Of those mothers who are employed, 64% work full-time (over 35 hours per week), and 36% work part-time. However, out of all of the mothers in the population, 49% work full-time. The population under study is made up of mothers of junior high school children in Santa Clara County.

Let E = size 12{E={}} {} employed, Let F = size 12{F={}} {} full-time employment

  • Find the percent of all mothers in the population that NOT employed.
  • Find the percent of mothers in the population that are employed part-time.
  • 24%
  • 27%
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The type of employment is considered to be what type of data?

Qualitative

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Find the probability that a randomly selected mother works part-time given that she is employed.

0.36

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Find the probability that a randomly selected person from the population will be employed OR work full-time.

0.7636

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Based upon the above information, are being employed AND working part-time:

  • mutually exclusive events? Why or why not?
  • independent events? Why or why not?
  • No,
  • No,
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[link] - [link] refer to the following: We randomly pick 10 mothers from the above population. We are interested in the number of the mothers that are employed. Let X = size 12{X={}} {} number of mothers that are employed.

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

B ( 10 , 0 . 76 ) size 12{B \( "10",0 "." "76" \) } {}

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Find the probability that at least 6 are employed.

0.9330

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We expect the Statistics Discussion Board to have, on average, 14 questions posted to it per week. We are interested in the number of questions posted to it per day.

  • Define X size 12{X} {} .
  • What are the values that the random variable may take on?
  • State the distribution for X size 12{X} {} .
  • Find the probability that from 10 to 14 (inclusive) questions are posted to the Listserv on a randomly picked day.
  • X = size 12{X={}} {} the number of questions posted to the Statistics Listserv per day
  • x = 0,1,2, . . . size 12{x=0,1,2, "." "." "." } {}
  • X ~ P ( 2 ) size 12{X "~" P \( 2 \) } {}
  • 0
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A person invests $1000 in stock of a company that hopes to go public in 1 year.

  • The probability that the person will lose all his money after 1 year (i.e. his stock will be worthless) is 35%.
  • The probability that the person’s stock will still have a value of $1000 after 1 year (i.e. no profit and no loss) is 60%.
  • The probability that the person’s stock will increase in value by $10,000 after 1 year (i.e. will be worth $11,000) is 5%.

Find the expected PROFIT after 1 year.

$150

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Rachel’s piano cost $3000. The average cost for a piano is $4000 with a standard deviation of $2500. Becca’s guitar cost $550. The average cost for a guitar is $500 with a standard deviation of $200.Matt’s drums cost $600. The average cost for drums is $700 with a standard deviation of $100. Whose cost was lowest when compared to his or her own instrument? Justify your answer.

Matt

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Horizontal boxplot with first whisker extending from 1 to 2, box from 2 to 5,  line at 4, and second whisker extending from 5 to 7.

For each statement below, explain why each is either true or false.

  • 25% of the data are at most 5.
  • There is the same amount of data from 4 – 5 as there is from 5 – 7.
  • There are no data values of 3.
  • 50% of the data are 4.
  • False
  • True
  • False
  • False
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[link][link] refer to the following: 64 faculty members were asked the number of cars they owned (including spouse and children’s cars). The results are given in the following graph: Histogram consisting of 5 bars with number of cars, from 0-7 in increments of 1, on the x-axis, and frequency, in increments of 0.1 from 0.15-0.45, on the y-axis. No bars exist for 4, 5, or 7. Bar 0 has a frequency of 0.075, 1 has 0.15, 2 has 0.45, 3 has 0.25, and 6 has 0.075.

Find the approximate number of responses that were “3.”

16

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Find the first, second and third quartiles. Use them to construct a box plot of the data.

2,2,3 size 12{2,2,3} {}

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[link][link] refer to the following study done of the Girls soccer team “Snow Leopards”:

Hair Style Hair Color
blond brown black
ponytail 3 2 5
plain 2 2 1
Suppose that one girl from the Snow Leopards is randomly selected.

Find the probability that the girl has black hair GIVEN that she wears a ponytail.

5 10 = 0 . 5 size 12{ { {5} over {"10"} } =0 "." 5} {}

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Find the probability that the girl wears her hair plain OR has brown hair.

7 15 size 12{ { {7} over {"15"} } } {}

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Find the probability that the girl has blond hair AND that she wears her hair plain.

2 15 size 12{ { {2} over {"15"} } } {}

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Questions & Answers

how does Neisseria cause meningitis
Nyibol Reply
what is microbiologist
Muhammad Reply
what is errata
Muhammad
is the branch of biology that deals with the study of microorganisms.
Ntefuni Reply
What is microbiology
Mercy Reply
studies of microbes
Louisiaste
when we takee the specimen which lumbar,spin,
Ziyad Reply
How bacteria create energy to survive?
Muhamad Reply
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Muhamad
they make spores
Louisiaste
what is sporadic nd endemic, epidemic
Aminu Reply
the significance of food webs for disease transmission
Abreham
food webs brings about an infection as an individual depends on number of diseased foods or carriers dully.
Mark
explain assimilatory nitrate reduction
Esinniobiwa Reply
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
Elkana
Examples of thermophilic organisms
Shu Reply
Give Examples of thermophilic organisms
Shu
advantages of normal Flora to the host
Micheal Reply
Prevent foreign microbes to the host
Abubakar
they provide healthier benefits to their hosts
ayesha
They are friends to host only when Host immune system is strong and become enemies when the host immune system is weakened . very bad relationship!
Mark
what is cell
faisal Reply
cell is the smallest unit of life
Fauziya
cell is the smallest unit of life
Akanni
ok
Innocent
cell is the structural and functional unit of life
Hasan
is the fundamental units of Life
Musa
what are emergency diseases
Micheal Reply
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
Lubega
Heyy Lubega hussein where are u from?
_Adnan
en français
Adama
which site have a normal flora
ESTHER Reply
Many sites of the body have it Skin Nasal cavity Oral cavity Gastro intestinal tract
Safaa
skin
Asiina
skin,Oral,Nasal,GIt
Sadik
How can Commensal can Bacteria change into pathogen?
Sadik
How can Commensal Bacteria change into pathogen?
Sadik
all
Tesfaye
by fussion
Asiina
what are the advantages of normal Flora to the host
Micheal
what are the ways of control and prevention of nosocomial infection in the hospital
Micheal
what is inflammation
Shelly Reply
part of a tissue or an organ being wounded or bruised.
Wilfred
what term is used to name and classify microorganisms?
Micheal Reply
Binomial nomenclature
adeolu
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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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