Florida International University
Business Statistics - STA 2023
Ms. Laura Reisert Instructor
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Chapter 7-A Supplelmentary Exercises
- According to the norms established for a reading comprehension test, eighth graders should average 83.2 with a standard deviation of 8.6. If 45 randomly selected 8th graders from a certain school district averaged 86.9, check the district superintendent's claim that his eighth graders are above average. Test at a significance level of .01.
- A psychologist hypothesizes that college students today sleep less during the night than college students of a generation ago. To test this hypothesis he randomly selects 400 college students and asks them to record the hours they sleep each night for a semester (similar to a study done 25 years ago). The old study showed college students sleeping an average of 7.32 hours each night with a standard deviation of 1.08 hours. If the current study yielded a mean of 7.24 hours, what conclusions can you draw with .05 significance?
- A sociologist examining a large apartment complex wishes to discover if the average number of persons per family unit differs significantly from the national mean of 4.8. She interviews 100 families in the complex obtaining a mean of 4.7 with a standard deviation of .80. What conclusions can you draw with a .02 level of significance?