document.write( "Question 727183: Based on data from the National Center for Health Statistics, N. Wetzel used the normal distribution to model the length of gestation for pregnant US woman ( Chance, Spring 2001). Gestation length has mean of 280 days with a standard deviation of 20 days.\r \n" );
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document.write( "a. Find the probability that gestation length is between 275.5 and 276.5 days. (This estimates the probability that a woman has her baby 4 days earlier than the due date) \n" );
document.write( "b. Find probability that gestation length is between 258.5 and 259.5 days. (This estimates the probability that a woman has her baby 21 days earlier than the due date). \n" );
document.write( "c. Find the probability that gestation length is between 254.5 and 255.5 days. (This estimates the probability that a woman has her baby 25 days earlier than the due date. \n" );
document.write( "d. The Chance article referenced a newspaper story about three sisters who all gave birth on the same day (March 11, 1998). Karralee had her baby 4 days early: Marrianne had her baby 21 days early: and Jennifer had her baby 25 days early. Use the results, parts a-c estimate the probability that all three woman have their babies 4, 21, 25 days early, respectively. Assume the births are independent events. \n" );
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