MODELING REAL LIFE In a survey of 920 U.S. teenagers, 81% said that helping others who are in need will be very important to them as adults. The margin of error is 3.3 %. a. Give an interval that is likely to contain the exact percentage of all U.S. teenagers who think that helping others who are in need will be very important to them as adults. Between % and b. The population of teenagers in the U.S. is about 21.05 million. Estimate the number of teenagers in the U.S. who think helping others will be very important to them as adults. Between about million and million