Stat 104 Section 5 - Problem Solutions

# Stat 104 Section 5 - Stat 104 Section Notes 5 Problem Solutions 1 A friend of mine is pregnant It is known that birth weights of babies in the US

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Problem Solutions 1) A friend of mine is pregnant. It is known that birth weights of babies in the US are approximately normally distributed with a mean of 3300 grams and a standard deviation of 375g [http://en.wikipedia.org/wiki/Birth_weight]. a) Babies that weigh less than 2500 grams are often put into intensive care units. What is the probability she has a baby that will be administered to the intensive care unit? b) What weight does her baby have to be in order to be in the heaviest 10% of all babies? 2) The daily high temperature for the first week in October in Boston is approximately Normally distributed with an average high of 66°F and a standard deviation of 7°F. a) Yesterday, the high temperature was 57.8°F. What is the probability that a day in the first week of October would have a high of 57.8°F or colder? b) What high temperature needs to be achieved in order to be in the top 1% of daily high temps in the first week of October? c) On the first day of October it got up to 83°F. What is the probability that a day in the first week of October would have a high of 83°F or warmer? 3) The annual winter snowfall in Boston has an average of 43 inches and a standard deviation of 21 inches. a) Let X be the random variable for the amount of snowfall Boston will get in a random winter. Do you believe X will be normally distributed? Could be… b) To date, Boston has received 68 inches of snow this winter. What is the probability that a winter season will have at least 68 inches of snow (assuming a normal distribution)? c) How much snow is needed to be in the top 1% of years in the amount of snowfall in Boston

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## This note was uploaded on 03/27/2012 for the course STATS 104 taught by Professor Michaelparzen during the Fall '11 term at Harvard.

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Stat 104 Section 5 - Stat 104 Section Notes 5 Problem Solutions 1 A friend of mine is pregnant It is known that birth weights of babies in the US

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