Suppose that Felisha is a librarian, and she read in a scholarly journal that the number of words in children's picture books published since 1950 is normally distributed with a mean of 802.2 words and a standard deviation of 88.0 words. She wishes to construct a confidence interval for the mean number of words in all children's picture books published after 2010, in case the number has changed in recent years. Felisha took a random sample of 20 children's picture books published after 2010 and counted the number of words in all 20 books. Her data is presented in the stem-and-leaf plot. 4 9 5 1 9 6 0 4 5 7 0 3 4 6 8 8 1 3 4 6 9 1 5 9 10 1 7 4951960457034688134691591017 Leaf Unit