Moderate prematurity refers to babies who are born between 28 and 32 completed weeks gestational age with a birth weight range between 1000 and 1500 grams. The length of time a baby has spent in the womb, or more specifically the number of completed weeks of pregnancy, is called the gestational age. Based on their ges- tational age and birth weight, premature babies are placed into categories of mild, moderate, and extreme prematurity. Mild prematurity refers to babies who are born between 33 and 36 completed weeks of gestation and/or have a birth weight between 1500 and 2500 grams. Moderate prematurity refers to babies who are born between 28 and 32 completed weeks of gestation with a birth weight range between 1000 and 1500 grams (about 2 lbs 3 oz and 3 lbs 5 oz).

Extreme prematurity refers to babies who are born before 28 completed weeks of gestation or have a birth weight of less than 1000 grams.

a. Generally speaking, the gestational time for human babies is approximately nor- mally distributed with an average of 40 weeks and a standard deviation of 2 weeks. (i) Calculate the probability of having a birth with mild prematurity. (ii) What is the probability of having a birth with extreme prematurity? (iii) Find the upper and lower quartiles for the gestation times. (iv) Would it be unusual to deliver a baby after only 24 weeks of gestation? Explain. (v) A randomly selected baby would be an age of less than X weeks to be one of the bottom 20% in gestational age. What is the value of x? (vi) Before what gestational time does 83.4% of the gestational time occur?

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