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The weight of a newborn babies born on time is normally distributed with a mean of 7.5 pounds in a standard deviation of 1.25 pounds. My nephew weighed 8.5 pounds find the probability of a baby weighs more than he did.

b. The weight of a newborn babies born on time is normally distributed with a mean of 7.5 pounds in a standard deviation of 1.25 pounds find the probability of baby weighs between 6.25 and 8.5 pounds.

User Divers
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1 Answer

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Answer:

(a) 0.2119

(b) 0.6294

Explanation:

μ = 7.5

σ = 1.25

(a)


Z=(x-\mu)/(\sigma)


=(8.5-7.5)/(1.25)


=0.8

P(Z>0.8) = 1 - Ф(0.8)

= 1 - 0.7881

= 0.2119

(b)


Z1=(x1-\mu)/(\sigma)


=(6.25-7.5)/(1.25)


=-1


Z2=(x2-\mu)/(\sigma)


=(8.5-7.5)/(1.25)


=0.8

P(-1<Z<0.8) = Ф(0.8) - Ф(-1)

= 0.7881 - 0.1587

= 0.6294

User Dionis
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