population Definition and 262 Threads

Hi guys, Got a semester exam on Population Genetics coming up in a few weeks and I'm really struggling to get my head around this concept. I've read a number of internet sources but am still not completely certain of what it is. Could anyone give me a basic overview, also I've got it...

Problem: Consider a random sample n from a population with probability distribution f(x,p) that depends on parameter p. Find the maximum likelihood estimator for p when f(x,p) = p^x (1-p)^1-x for x=0,1

(Apologies for cross-posting this in the Nuclear and Differential Equations forums. I'm new to posting on Physics Forums and not entirely sure where it belongs. Mods, please feel free to delete/move as appropriate.) I am trying to create a decay chain simulator in Excel that my pupils can use...

(Apologies for cross-posting this in the Nuclear and Differential Equations forums. I'm new to posting on Physics Forums and not entirely sure where it belongs. Mods, please feel free to delete/move as appropriate.) I am trying to create a decay chain simulator in Excel that my pupils can use...

Ok in my physics class we are doing planetary motion and stuff, we started talking about how the population of the Earth affects the force of gravity. So my question is does it? Also if say all of Earth's population was concentrated to one hemisphere and everyone jumped at the same time would it...

Homework Statement In summer months, female aphids reproduce by parthenogenesis, giving birth to females from unfertilized eggs. These females mature within 24 h and begin reproducing in the same way. Assume that each female aphid produces two females the day after she herself is born, then...

I want to calculate expected variance of a randomly selected subset of a population. The particular problem I am trying to solve is as follows. There is a set of values X = {x1, ... , xn}. Let Y be subset of X with n-1 elements. I think that if Y is selected at random (that is, if is...

I'm working on my statistics homework. The professor gave us two problems with the same probability (p), but with different number of trials (n); p= .3 and n= 2 in one and n= 200 in the other one. He told us one was the actual population and the other one was a sample. I did both problems and...

I thought that they were both the same, they're mean of the sample aren't they?

Homework Statement The population of koala bears within a nature reserve at time t is greater than or equal to 0 is given by the function N(t) = 200t/4 + t Determine a)the lim as t-->infinity (the limiting population size) b)when the population is...

1. So for my computer science course I was given the homework on how to write a program on population growth. The serious dilemma is how to set up the equation. Here are the variables that are given to me: J = original number of Jackalopes (the imaginary animal that my teacher used) Y =...

Homework Statement Homework Equations <see above>The Attempt at a Solution I'm a bit unsure how to set this up to solve for a solution. Any advice? Its obviously a separable differential equation. But I'm unsure what it is I'm looking for. This looks different then some population...

For the period from 1900 to 1980, calculate the log base e (ln) of the world population values and plot these values on the vertical axis against the year on the horiontal axis. Draw the best straight line you can through these points and determine its slope, k. What is the exponential...

If there was an isolated human population that eventually became unable to breed with any humans outside of their population, would they become classified as a different species than us?

I have the following problem: Suppose there is a survey of persons with two properties each (a and b). a can take a relatively small number of values (say the political inclination: Conservative, Liberal, Socialist, or Other) the other one b can take a large number of values (say: the country...

in a scientific study, the size , p of a population at t hours is being studied. Initially p = 560 and after 6 hours, p is found to be 1218. In a simple model of population growth, the rate of the population is taken to be proportional to the population at that time. Using this model predict...

Homework Statement The population of the world was 5.7 billion people in 1995 and 6.2 billion in 2008. Assuming exponential growth by what year will the population reach 11 billion? The Attempt at a Solution i started by trying to find R but am not sure the my way is right...

Homework Statement The fish population in a lake is attacked by a disease at time t=0 with the result that the size P(t) of the population at time t: dP/dt= -k*sqrt(P) where k is a positive constant. If there were initially 90,000 fish in the lake and 40,000 were left after 6 weeks, when...

Homework Statement Consider a population whose number we denote by P . Suppose that b is the average number of births per capita per year andd is the average number of deaths per capita per year. Then the rate of change of the population is given by the following differential equation...

Homework Statement Consider an infinite population with the mean of 160 and a standard deviation of 25. A random size 64 is taken from this population. What does the standard deviation of the sample mean equal to? Homework Equations How do I answer this question without a given...

Could anyone explain me (or give reference to a book) what is coherent population trapping (in optics). Is it somehow connected with Electromagnetically Induced Transparency (I also don't know how it works). Thanks for any replies.

Suppose rabbit populations grow exponentially with a growth rate of 20% per year. If P(t) is the population at any time t and 1000 is the initial (t=0) population of rabbits, what is the population of rabbits in 10 years? Use the DE model: P ' = kP with k = .1 and P(0) = 1000. Plz help me

Working on some DE homework and need a tad bit of guidance. I got fairly far, I'm just wondering what the next step is. Homework Statement The rate of change of an alligator population P is proportional to the square of P. The swamp contained a dozen alligators in 1988, two dozen in 1998...

Hi could someone please explain how this can be done please 1. The population P satisfies the differential equation dP dt = X(P) − Y(P) , where X(P) is the birth rate and Y(P) is the death rate. Find the general solution P(t) to this differential equation for the case that X(P) = k1(sqrt)P...

Hi could someone please explain how this can be done please 1. The population P satisfies the differential equation dP dt = X(P) − Y(P) , where X(P) is the birth rate and Y(P) is the death rate. Find the general solution P(t) to this differential equation for the case that X(P) =...

Homework Statement A culture begins with 100,000 bacteria and grows to 125,000 bacteria after 20 min. What is the doubling period to the nearest minute? Homework Equations Current=Original(rate)^time The Attempt at a Solution I can get make the first part out...

Homework Statement The population of a country is divided in two groups: People who live in rural areas (R(t)) and people who live in urban areas (U(t)). People move from rural to urban areas with a rate m and from urban to rural areas with rate n. a) Introduce the fraction of...

Suppose the population variance \theta is to be estimated from observations Y_1, Y_2, \dots, Y_n using \hat{\theta} = \left(\frac 1 n \sum_{i=1}^n (Y_i - \overline Y)^2\right) where \bar{Y} is the mean. when it didnt say which distribution Y_is are? thanks

I have this delete s275x05.txt; diary s275x05.txt clear; clc; close all; echo on % % Stewart 275/05 % year=[0:1]; % n+1 = year + 50 pop=[728 906]; p=polyfit(year,log(pop),2) plot(year,pop,'o','MarkerFaceColor','r') hold on x=[0:0.01:6]; y=exp(polyval(p,x)); plot(x,y) hold on %part...

Homework Statement http://img14.imageshack.us/img14/1286/99892583.jpg Homework Equations in the pictureThe Attempt at a Solution so i know that p(0)e^2k = 950 p(0)e^8k = 9500 how do i find k? for p(0) i get 440.950939 is that right? btw. ignore the answers in the picture

Homework Statement (a) Use a graphing calculator or computer to fit an exponential function to the data. Graph the data points and the exponential model. How good is the fit? (b) Estimate the rates of population growth in 1800 and 1850 by averaging slopes of secant lines. (c) Use the...

Can anyone help me to solve this question: A random sample of twenty-five apples is obtained from a normal population distribution with a mean of 80 grams and a standard deviation of 5 grams. Another random sample of 36 apples is obtained from a population distribution having a mean of 75...

Homework Statement The differential equation \frac{dP}{dt} = P(a - bP) is a well-known population model. Suppose the DE is changed to: \frac{dP}{dt} = P(aP - b) Where a and b are positive constants. Discuss what happens to the population P as time t increases. Homework Equations...

Each of a group of 20 tennis players is given 2 rackets, 1 having nylon strings and the having gut strings. After several weeks of playing with 2 rackets, each player will be asked to state a preference for one of 2 types of strings. Let p denote the proportion of all such players who prefer...

Human population verses time, Fourier transform of that "function". Let the human population of the Earth be plotted verses time. Assume that this function is almost continuous. What would a Fourier Time Transform of that function look like? Is there a "strong" exponential component of...

Hello everybody! I have been reading about the evolution of population growth since 1950 till now. It had many factors such as development of technology, of medecine, ... Now i want to calculate the future population growth let's say for example for 2050. In those readings i found also those...

Hello everybody! I have been reading about the evolution of population growth since 1950 till now. It had many factors such as development of technology, of medecine, ... Now i want to calculate the future population growth let's say for example for 2050. In those readings i found also those...

Imagine that I want to rank the top 3 foods of all time. I want to ask ten different people to answer this question. So I get answers such as: Mashed Potatoes > Artichokes > Carrots Beef Jerky > Mashed Potatoes > French Fries ...etc. Is there an established method or algorithm for...

1. The problem statement The DE governing a fish pop. P(t) with harvesting proportional to the population is given by: P'(t)=(b-kP)P-hP where b>0 is birthrate, kP is deathrate, where k>0, and h is the harvesting rate. Model assumes that the death rate per individual is proportional to the...

A friend of mine said that currently, the "wealthy" 1.5 billion people on Earth consume as much as the poor other 4.5 billion. He also said there are not enough resources (corruption, etc, aside) to have the others live the "rich" life style. Which begs the question... how much human life can...

i've always been told that the human pop has been going steadily up and up (6E9 in 1999 i think). a site like this http://www.populationaction.org/ seems to support this. now someone has told me this is all a lie by the elite to kill off large segments of the world. ok that's fine - i have no...

Feeling a bit rusty on my probability - Say you have 70,000,000 people in a country and a small town with 13,700 people. Now, say 3,000 - 5,000 people of the 70,000,000 people become infected with cancer per year. What are the chances 5 people from the small town get infected in one...

The culture is in a standard 10 gallon tank (20"x10"x12"). I started with about 200 daphnia (<1mm to 3mm). I would like to know where I am at right now.

Homework Statement A parent isotope has \tau_\frac{1}{2}=\delta. Its decays through a series of daughters to a final stable isotope. One of the daughter particles has the greatest half life of \tau_\frac{1}{2}=\alpha-- the others are less then a year. At t=0 the parent nuclei has N_0 nuclei...

Let c be a positive number. A differential equation of the form below where k is a positive constant, is called a doomsday equation because the exponent in the expression ky^(1+c) is larger than the exponent 1 for natural growth. An especially prolific breed of rabbits has the growth term...

Homework Statement A population of wolves grows according to the function N(t)=(10N0)/(1+9e^(-t/4)), where t is in years and N0 is the initial amount. How long from t=0 will the population take to double? Homework Equations Refer to below heading. The Attempt at a Solution Not...

Homework Statement The population of a country is growing exponentially. The population in millions was 120 in 1970 and 150 in 1980. (a) What is the population t years after 1970? (b) How long does it take the population to double? (c) When will the population be 400 million...

A population grows at a constant relative rate. After 10 months the population grows to 72, and after 18 months the population grows to 96. Find C and k. the answer I got was c=50.25 and k=.0359 can somebody just double check for me? I don't know if the method I was used was correct.

In the experiment of CPT( coherent population trapping),we always consider some questions,such as :the temperatue of rubidium vapor cell, the pressure of the buffer gas ,and incidence intensity of laser. if we just want to increase the amplitude of the CPT signal ,what should we do. And I hope...

Population of Mexico. In 2006 the population of Mexico was 107.4 million. If Mexico’s population continues to grow at an annual rate of 1.43%, then the population in 2028 will be 107.4(1.0143)14 <-------- is an exponent a) Find the predicted population in 2020 to the nearest tenth of a...