In the year 2014, infants born after a gestation period of 32 to 35 weeks had a
ID: 3176978 • Letter: I
Question
In the year 2014, infants born after a gestation period of 32 to 35 weeks had a mean weight of 2600 grams and a standard deviation of 750 grams. In the same year, infants born after a gestation period of 40 weeks had a mean weight of 3700 grams with a standard deviation of 500 grams. Baby Antonio is a 34-week - gestation period infant that weighed 3200 grams. Determine the z - score for Baby Antonio. Baby Luz is a 40-week-gestation period infant that weighed 4500 grams. Determine the z - score for Baby Luz. Which baby, Antonio or Luz, weighed more relative to the gestation period? Explain. How much would Baby Antonio have weighed with a 40-week-gestation period ? How much would Baby Luz have weighed with a 34-week-gestation period ?Explanation / Answer
1)34week baby (born 32 to 35 weeks, so mean = 2600 and s.d. = 750)
z = (3200 – 2600) / 750 = 0.80 (rounded to two decimal places)
2)40week baby (born after 40 weeks, so mean = 3700 and s.d. = 500)
z = (4500 – 3700) / 500 = 1.6 (rounded to two decimal places)
3)The same zscore means the baby born at 35weeks weighs MORE relative to other babies its same age. The 35week baby weighs 0.8 standard deviations MORE than the average baby born the same week he was born. The 41week baby weighs 1.6 standard deviations MORE than the average baby born the same week he was born. SO, this baby born in week 35 at 3200 grams weighs LESS than the baby born at 41 weeks who weighs 4500 grams RELATIVE to other babies that same age
THEREFORE LUZ WEIGHED MORE
4) Z SCORE FOR ANTONIO = 0.8
THEREFORE 0.8 = (WEIGHT - 3700)/500
WEIGHT = 4100 GRAMS
5)
Z SCORE FOR LUZ = 1.6
THEREFORE 1.6 = (WEIGHT - 2600)/750
WEIGHT = 3800 GRAMS