Snoring. According to the British United Provident Association (BUPA), a major health care provider in the U.K., snoring can be an indication of sleep apnea which can cause chronic illness if left untreated. In the U.S.A., the National Sleep Foundation reports that 36.8% of the 995 adults they surveyed snored. Of the respondents, 81.5%

were over the age of 30, and 32% were both over the age of 30 and snorers.

a) What percent of the respondents were 30 years old or younger and did not snore?

b) Is snoring independent of age? Explain.