In a Statistics Class, the Average Grade on the Final

Essay

In a statistics class, the average grade on the final examination was 75 with a standard deviation of 5. Use Chebyshev's theorem to answer the following questions.
a.At least what percentage of the students received grades between 50 and 100?
b.Determine an interval for the grades that will be true for at least 70% of the students. (Hint: First, compute the Z-score.)