Open Question: Binomial Random variables?

Open Question: Binomial Random variables?

Find the probability that in a family of 4 children there will be (a) at least 1 boy (b) atleast 1 boy and 1 girl. Assume that the probability of a male is 1/2.

An insurance salesperson sells policies to 5 men, all of identical age and in good health. According to the actuarial tables, the probability that a man of this particular age will be alive 30 years is 2/3 : Find the probability that in 30 years (a) all 5 men, (b) at least 3 men, (c) only 2 men, (d) none will be alive


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Open Question: (Statistics) Compute for a point estimate for the proportion of students for at least 3 variables.?

Open Question: (Statistics) Compute for a point estimate for the proportion of students for at least 3 variables.?

3.Which source is the most reliable for you for research work?
Information from internet sites
Books
Newspaper articles

The data can be found here:
https://spreadsheets.google.com/lv?authkey=CL2FxaoM&authkey=CL2FxaoM&hl=en&hl=en&key=tEDcIPNRpkIe1EHEjNtBDwQ&type=view&gid=0&f=true&sortcolid=35&sortasc=true&rowsperpage=250

You have to scroll far to the right under Internet as Academic Reference; question 3

Somebody please help me with this, it would be much appreciated :D


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Open Question: differential equation; separation of variables dx(t)/dt = k(a-x(t))(b-x(t))?

Open Question: differential equation; separation of variables dx(t)/dt = k(a-x(t))(b-x(t))?

Start: dx/[(a-x)(b-x)] = kdt

1/(a-x)(b-x) = [A/(a-x)] +B/(b-x) => A = 1/(b-a) B=1/(a-b)

The integrand is then [1/(b-a)][1/(a-x) - 1/(b-x)], which integrates to [1/(b-a)]ln{(b-x)/(a-x)} and kdt just integrates to kt.


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