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.

b. The birth weight of a baby is approximately normally distributed with an average of 3.4 kg and a standard deviation of 800 grams. (i) Calculate the probability of having a birth with moderate prematurity. (ii) What is the probability of having a birth with extreme prematurity? (iii) What is the probability of having a baby weighing at least 6 kg? Do you think it is highly unlikely to have a baby with this weight? Explain. (iv) A randomly selected baby will weigh more than X kg to be one of the top 5% in weight. What is the value of x? (v) Above what weight do 87.70% of the weights occur? (vi) Suppose that on another planet the baby (may not be human) birth weight X follows the normal distribution. The probability that X exceeds 4 kg is 0.975, and the probability that X exceeds 5 kg is 0.95. Find and o. Are these values comparable with the expected weight of a human baby? Explain.

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