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In a study, people were observed for about 10 seconds in publicplaces, such as malls and restaurants, to
          determinewhether they smiled during the randomly chosen 10-secondinterval.  The researchers observed
          600people who were aged 20 years or younger, and 47% of these peoplesmiled.  The researchers also
          observed975 people who were aged 21 years or older, and 32% of these peoplesmiled.  (Treat this data
          asif it were two simple random samples.)
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          a)  Fillin the following table.
| Age Range |
          | 0–20 | 21+ |
Number who smiled () | | |
Total number in sample ( | | |
Proportion who smiled () | | |
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          b)  Determineand interpret the 95% confidence interval estimate of thedifference between the population
              proportions.
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          c)  Whatdoes this suggest about how often people in these age groupssmile?  Does one group smile
               significantlymore often than the other?  If so, which one?
