While there is much debate, several health authorities have concluded that a vitamin D level of 30 is adequate for maintaining one's health. Suppose this is the mean vitamin D level for adults in the...

While there is much debate, several health authorities have concluded that a vitamin D level of 30 is adequate for maintaining one's health. Suppose this is the mean vitamin D level for adults in the United States. What is the probability that a randomly selected adult from the United States has a vitamin D level lower than 25? Suppose the standard deviation is 6 and that the vitamin D levels for adults in the United States follow a normal distribution.