Question

Vitamin D is essential for strong, healthy bones. Our bodies produce vitamin D naturally when the skin is exposed to sunlight, or it can be taken as a dietary supplement. Although the bone disease rickets was largely eliminated in English during the 1950s, some people there are concerned that this generation of children is at increased risk because they are more likely to watch television or play computer games than spend time outdoors. Recent research indicated that about 20% of British children are deficient in vitamin D. Suppose doctors test a group of elementary school children. (a) What is the probability that the first 10 children tested are all okay? (b) They test 50 Grade 3 students. Find the mean and standard deviation of the number who are deficient in vitamin D. (c) If they test 320 children at this school, what is the probability that no more than 50 of them have the vitamin deficiency?

Answer 1