Statistics +Probability 問題(急)－bxzbthf的部落格

標題:

Statistics +Probability 問題(急)

發問:

TastyMilk sells bottles of milk in two sizes. The amount in each bottle ,in ml ,is normally distributed with mean and variance as shown in the following table.Small mean: 252(ml)Large mean:1012(ml)Small variance:4 (ml square)Large variance:25 (ml square)i)Find the probaility that a randomly selected... 顯示更多 TastyMilk sells bottles of milk in two sizes. The amount in each bottle ,in ml ,is normally distributed with mean and variance as shown in the following table. Small mean: 252(ml) Large mean:1012(ml) Small variance:4 (ml square) Large variance:25 (ml square) i)Find the probaility that a randomly selected large bottle will cointain an amount between 1000 and 1020ml ii)If s small bottle and a large bottle are selected randomly, find the probaility that the total number in the two bottles will exceed 1300ml iii)A bottle of each size is selected randomly.Find the probaility that the large bottle contains less than four times the amount in the small bottle. THX

最佳解答:

S~N(252, 4), L~N(1012, 25) (i) P(10001300) = P(z > (1300-1264)/sqrt(29) ) = p(z >6.685) ~ 0 (iii) Let Y = L-4S ~ N(4, 89) P(Y<0)=P(z < -4/sqrt(89)) = P(z < -0.424) = 0.33576

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