The librarian at the local school claims that, on average, the books in the library are more than 20 years old. To test this claim, a student takes a sample of 30 books, and records the publication date. The 30 books produce an average age of M = 23.8 years with a standard deviation of 8.22 years. A. Single-sample z-test B. Single-sample t-test C. Independent samples t-test D. Related samples t-test (repeated measures or matched samples) E. Correlation

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