A random sample of 30 receipts for individuals shopping at the Community Drug Store showed the sample mean to be'x = $28. 19 with sample standard deviation s= $4.06.

a. Use Chevyshev's theorem to find the smallest interval centered on the mean in which we can expect at least 75% of the data to fall. 

b. Use Chevyshev's theorem to find the smallest interval centered on the mean in which we can expect at least 88.9% of the data to fall.

c. Use Chevyshev's theorem to find the smallest interval centered on the mean in which we can expect at least 93.8% of the data t o fall.