Consider a sample with a mean of 60 and a standard deviation of 4. Use Chebyshev's theorem to determine the percentage of the data within each of the following ranges (to the nearest whole number).

a. 40 to 80, at least %

b. 45 to 75, at least %

c. 51 to 69, at least %

d. 47 to 73, at least %

e. 44 to 76, at least %