Assume that the duration of human pregnancies can be described by a normal model with mean...

Assume that the duration of human pregnancies can be described by a normal model with mean 266 days and standard deviation 12 days. Complete parts

a) What percentage of pregnancies should last between 275 and 280 days? _________%

(Round to one decimal place as needed.)

b) At least how many days should the longest 30% of all pregnancies last?

P(X greater than or equals≥________)=0.30

(Round to one decimal place as needed.)

c) Suppose a certain obstetrician is currently providing prenatal care to 90 pregnant women. Let y represent the mean length of their pregnancies. According to the central limit theorem, what is the mean and standard deviation SD(y overbary) of the normal model of the distribution of the sample mean, y overbary?

The mean is _________.

SD(y overbary)equals=__________

(Round to two decimal places as needed.)

d) What is the probability that the mean duration of these patients' pregnancies will be less than 265 days?

P(y overbaryless than<265)equals=________

(Round to three decimal places as needed.)

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Expert Solution

orchestra answered 1 year ago

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