population Definition and 278 Threads

Population is the term typically used to refer to the number of people in a single area. Governments conduct a census to quantify the size of a resident population within a given jurisdiction. The term is also applied to animals, microorganisms, and plants, and has specific uses within such fields as ecology and genetics.

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  1. T

    Population model: dP/dt = k sqrtP

    Homework Statement Suppose that when a certain lake is stocked with a population P of fish, the birth and death rates \alpha and \beta are inversely proportional to \sqrt{P} , so that \frac{dP}{dt} = k \sqrt{p} Find P(t) if P(0)=C The Attempt at a Solution \frac{dP}{\sqrt{p}} = k dt...
  2. L

    Iraq war over population control?

    i was just reading about chinas 1.4 boy to girl birth ratio and it has me wondering is this going on in the united states? it seems to me like finding the right girls has always been a fight. shotgun wedding :eek: i hope not.
  3. G

    Population proportion *statistics*

    Homework Statement Harley-Davidson motorcyles make up 14% of all the motorcyles registered in the United States. You plan to interview an SRS of 500 motorcyle owners. a) what the approximate distribution of the proportion of your sample who owns harleys? b) Is your sample likely to contain...
  4. P

    Population Modeling using DE's

    Hi, I was wondering if anyone out here on a Friday night could help me understand population modeling. Here is what I have as a problem (this is pretty simple because my goal here is to understand the thinking behind the madness :rolleyes: ) - The population of a certain community is...
  5. D

    Medical IQ Question - Dealing with population mean.

    I was discussing Plato's Republic in class and we got into eugenics. Anyway, I remember hearing somewhere that IQ always deviates towards the population mean, and, therefore, it is not true that eugenics will result in benefits for the population (at least when done on the basis of IQ). Is this...
  6. H

    Answer:Limiting Population: Solving Logistic Equation with P_0

    I'm stuck on what to do here. The question reads Consider a population P(t) satisfying the logistic equation dP/dt = aP-bP^2, where B = aP is the time rate at which births occur and D = bP^2 is the rate at which deaths occer. If the intial population is P(0) = P_0 (supposed to be P sub not)...
  7. J

    Population Dynamics: Find & Classify Equilibrium Points

    Two species x, y compete for the same limited food supply according to the model x'=3x-2x^2-2xy y'=4y-3y^2-2xy Find and classify the equilibrium points. Please please can anyone help me with this??
  8. Garth

    Population III detected at last?

    Is the identification of a GRB with a 'hyper-nova' at z = 6.295 when the universe was 900 Myrs old (standard model) the first detection of the long awaited Population III stars that caused the 'first light'?Ancient blast comes to light That article speaks of a mass of 20MSolar, but I don't...
  9. E

    Solving for K and Time when P=44 in Alligator Population Problem

    I am having a problem with finding the constant K in This problem. The time rate of change of an alligator population P in a swamp is proportional to the square root of P. The swamp contains 9 alligators in 2000 and 25 alligators in 2005. When will there be 44 alligators in the swamp? I...
  10. Z

    Solve 1/P*dP/dt = b+aP for Population Growth

    I am quite sure the first approach is to use partial fractions but I am unclear how to finish this equation 1/P*dP/dt=b+aP
  11. Pengwuino

    US Population: 300,000,000 come October

    http://www.nytimes.com/2006/01/13/national/13baby.html?ei=5090&en=7986dfa5eaaf53ed&ex=1294808400&partner=rssuserland&emc=rss&pagewanted=all If any of you want to have that baby, you better hurry the heck up.
  12. J

    Exponential population decay word problem

    Suppose that in any given year, the population of a certain endangered species is reduced by 25%. If the population is now 7500, in how many years will the population be 4000? Well, I know that the formula for this is P(t) = Cekt. I just can't figure out the value of k. i did 7500 x .25 =...
  13. ranger

    Azeroth: Population 5 million and counting

    http://www.gamespot.com/news/6141517.html Is it just me or is that a lot of people playing one game. Whats so special about World of Warcraft anyway? Any hardcore WoW players on PF.
  14. R

    Question about vaiance, population and sample

    In the October edition of the magazine, Active Trader, a reader writing in Chat Room, "Deviating from deviation?" asks that in explaining last month the viaiance, why did you not in your example divide by two? {(8-9)^2 + (9-9)^2 +(10-9)^2}/3 = .667. The explanation given is nothing more...
  15. A

    Extrapolating Human Population to 5000 B.C

    The Earth's current Human population is 6 Billion. Some time in 1940 the world population was 3 billion and around 1750 the population was about 500 million. Is there a scientific method to extrapolate the Human population for the date 5000 b.c? Thanks.
  16. G

    Solving Diff. Equations: Population Growth & Changes

    Hello I am having major difficulties with two Differential equation. 1. If I have the equation P=2000/(1+9e^.06t). where p=population and t=time. How do I work out when the population is growing the fastest? To work this question out do I just make t the subject and diff twice and let it...
  17. T

    Mulliken Population when using double zeta basis

    Is there anyone who can help me? I was bothered by the negative occupation in atomic orbital like 5p here. I don't understand what it means. By the way, 6.00 here is the total number of charges. # 5s 5s 5py 5pz 5px 5py 5pz 5px 4dxy 4dyz...
  18. D

    Differential equations - population model

    "Suppose that a certain population satisfies the initial value problem \frac{dy}{dt}=r(t)y - k, \qquad y(0)=y_0 where the growth rate r(t) is given by r(t)=\frac{1+\sin t}{5} and k represents the rate of predation. (a) Suppose that k=\frac{1}{5}. Plot y versus t for several...
  19. P

    Population Growth - Bacteria Culture at 300 to 30000 in 4.32 Hrs

    A bacteria culture starts with 300 bacteria and grows at a rate proportional to its size. After 3 hours, there are 9000 bacteria A.) Find an expression for the number of bacteria after t hours. for this part, i got 300*e^{1.133732*t} B.) Find the number of bacteria after 4 hours. well...
  20. E

    Will Population Growth Outpace Currency Availability?

    The population is increasing but the sum total of money remains the same. Is it inevitable that there will be more people than the limited amount of currency can supply for?
  21. A

    How Does Wolf Population Growth Impact Moose Numbers?

    The population of the wolves influences the change in population of the mooses. When the population of the wolves increase, the mooses' population also increase. From the population growth formula of the wolves delta N/delta t = rN(K-N)/K which factor affects the population of the mooses...
  22. F

    Population Problem: Solve for When 51003 in Brampton

    -------------------------------------------------------------------------------- Hi everyone I'm having trouble with this problem, while preparing for my calculus test this Monday...could anyone help me figure out the solution...I know that I must use the formula P=P(original)e^kt where...
  23. C

    Fish Pond Population Growth: Is a Constant?

    Alright, my teacher the sadist gave us an assignment over the holidays, and so far, everyone in my class has gotten all but this. The equation is representative of the population growth of fish in a fish pond. p= m / 1+ae to the -kt p is the intial population, m the carrying capacity...
  24. P

    Solar energy flux, Earth's population

    Solar energy flux, Earth's population... Hi everyone :smile: I have this one question from my optics course that has me totally stumped. It reads "Solar energy flux at Earth's position is about 1.7kW/m^2. Estimate the maximum possible population of the Earth." I've looked through my...
  25. B

    Does Time Travel Affect The Worlds Population?

    Does Time Travel Affect The Worlds Population? This is the worlds current population. http://www.worsleyschool.net/socialarts/world/population.html
  26. G

    Rate of increase of population of a country

    ) IF the rate of increase o f population of a country is 3 percent every year, by what factor does it increase every 10 years? What percentage increase will double the population every ten years? ***N= Pe^(k*t) <---this is the equation, not sure how to use it...
  27. S

    Population Explosion: 18B+ People - Will Society Cope?

    there is a definite risk that in the following century human population may increase to above 18 billion (it is 10 billion right now, isn't it?) with maximum increase in the third world and slight decrease in first world. do you think human society can deal with such population demographics...
  28. J

    What Will the Population Be in 1997 Based on Exponential Growth?

    The following question is from a textbook..and I can't seem to solve it. Can someone help. --============================== The population of a midwestern city follows the exponential law. If the population decreased from 900,000 to 800,000 from 1993 to 1995, what will the population be in 1997?
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