Starting in the 1970s, medical technologyallowed babies with very low birth weight
Chapter 0, Problem 22.28(choose chapter or problem)
Starting in the 1970s, medical technologyallowed babies with very low birth weight (VLBW, less than 1500 grams, about3.3 pounds) to survive without major handicaps. It was noticed that thesechildren nonetheless had difficulties in school and as adults. A long-term studyhas followed 242 VLBW babies to age 20 years, along with a control group of233 babies from the same population who had normal birth weight.8(a) Is this an experiment or an observational study? Why?(b) At age 20, 179 of the VLBW group and 193 of the control group hadgraduated from high school. Is the graduation rate among the VLBW groupsignificantly lower than for the normal-birth-weight controls?
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