a. Nationally, the population as a whole watches 6.2 hours of TV per day. A random sample of 1,017 senior citizens report watching an average of 5.9 hours per day, with a standard deviation of 0.7. Is...

a. Nationally, the population as a whole watches 6.2 hours of TV per day. A random sample of 1,017 senior citizens report watching an average of 5.9 hours per day, with a standard deviation of 0.7. Is the difference significant?

b. The same sample of senior citizens reports that they belong to an average of 2.1 voluntary organizations and clubs, with a standard deviation of 0.5. Nationally, the average is 1.7. Is the difference significant?