In an all boys school, the nights of the student body are normally distributed with a mean of 71 inches and a standard deviation of 3 inches. Using the empirical rule, what percentage of the boys are between 65 and 77 inches tall?

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Marina baked cookies. she gave 3/4 of the cookies to the scout bake sale. she shared the remaining 6 cookies with her friends. how many cookies did marina bake?

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?