Vitamin D, whether ingested as a dietary supplement or produced naturally when sunlight falls upon the skin, is essential for strong, healthy bones. The bone disease rickets was largely eliminated during the 1950s, but now there is concern that a generation of children more likely to watch TV or play computer games than spend time outdoors is at increased risk. A recent study of 3100 children randomly selected found 23% of them deficient in vitamin D.
a. Construct a 98% confidence interval for the true proportion of children who are deficient in vitamin D. Select the correct choice below and fill in any answer boxes within your choice.
b. Explain carefully what the interval means.
c. Explain what "98% confidence" means.
d. Does the study show that computer games are a likely cause of rickets?