Question

gasoline wholesale distributor has bulk storage tanks holding a fixed supply. The tanks are filled every Monday. Of interest to the wholesaler is the proportion of this supply that is sold during the week. Over many weeks, this proportion has been observed to be modeled fairly well by a beta distribution with alpha = 4 and beta = 2. Find the probability that at least 90% of the stock will be sold in a given week? a. 0.07 b. 0.05 c. 0.09 d. 0.06 e. 0.08

Answer 1

Answer:

e. 0.08

Step-by-step explanation:

In the question above, a certain quantity of goods was supplied while a specific quantity of goods was sold per week. In a given week, if the number of proportion sold is X, therefore:

f(x) = {Γ(4+2)/Γ(4)Γ(2) x^3 (1-x), 0≤x≤1 ; 0, elsewhere

and

P(X greater than 0.9) =  $\int\limits^1_ {0.9} \, 20(x^{3} - x^{4}) dx$ = 20*{(y^4/4)[1,0.9] - (y^5/5)[1,0.9]} = 20*{(0.25 - 0.164) - (0.20 - 0.118)}  = 20*{0.086 - 0.0819} = 20*0.0041 = 0.082

Therefore the probability of the proportion sold is approximately 0.082