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The best-paid 20 tennis players in the world have earned millions of dollars during their careers and are famous for having won some of the four “Grand Slam” tournaments. Somewhat less famous players who are in positions 20 through 100 in the earnings’ rankings have also garnered large sums. The following data (in millions of dollars) correspond to the earnings of 15 randomly selected players classified somewhere in positions 20 through 100. They are also stored in the data frame Top20.

Compute a 94% confidence interval for the average earnings of players classified between positions 20 and 100 of the ranking. (Source: http://www.atptennis.com/en/)