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Interpreting the variance and standard deviation: The distribution of grades in an introductory finance class is normally distributed, with an expected grade of 65. If the standard deviation of grades is 5, in what range would you expect 90 percent of the grades to fall?        

(Round all answers to two decimal places, i.e., 23.07)

(Hint: Think in terms of what the expected highest and lowest scores would be for 95% of the students taking the exam.)                     
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Number of Standard Deviations                             Fraction of
from the Mean                                             Total Observations
1.000                                                                     68.26%
1.645                                                                      90%
1.960                                                                      95%
2.575                                                                       99%