Probability : Mean, Standard Deviation and Recurrence Relation

In order to test a vaccine, we have to find patients with a certain blood type, that is found in 20% of the population. Model W, the number of people sampled until we have found one with thhis blood type; X, the number sampled to find four with the blood type; and Y, the number with this blood type among 20 people. Find the means and standard deviations of W, X and Y.

A mean and standard deviation are found. A recurrence relation is investigated. The solution is detailed and well presented. The response received a rating of "5" from the student who originally posted the question.

1. If a person invests in a tax-sheltered annuity, the money invested, as well as the interest earned, is not subject to taxation until withdrawn from the account. Assume that a person invests $2000 each year in a tax-sheltered annuity at 10 percent interest compounded annually. Let An represent the amount at the end of n year

Suppose a sequence satisfies the given recurrence relation and initial conditions. Find an explicit formula for the sequence
s(subk)=-4s(subk-1)-4S(subk-2), for all integers k>or equal to 2
s(sub0)=0,S(sub1)=-1

1. Pauline takes a loan of S dollars at an interest rate of r percent per month, compounded monthly. She plans to repay the loan in T equal monthly installments of P dollars each.
a) Let a(subscript n) denote the amount Pauline owes on the loan after n months. Write a recurrencerelation for a (subscript n).
b) Solve the rec

Please help with the following discrete math involving recurrencerelations, compound interest, polynomials, number of combinations and iteration.
14. Individual membership fees at the evergreen tennis club were $50 in 1970 and have increased by $2 per year since then. Write a recurrencerelationand initial conditions for

The random variable X is the number of houses per month sold by a realtor. The probability distribution is given below. Find the mean andstandarddeviation of X:
X (houses sold) / f(x)
____________________________________________
(0 , 0.24)
(1 , 0.01)
(2 , 0.12)
(3

A frequency distribution is shown below. Complete parts (a) through (e).
The number of dogs per household in a small town
Dogs 0 1 2 3 4 5
Households 1157 417 168 45 26 16
a) Use the frequency distribution to construct a probability distribution.
X