Use the Empirical Rule.
Use the sample statistics from Exercise 30 and assume the number of households in the sample is $40 .$
(a) Estimate the number of households whose monthly utility bills are between $\$ 54$ and $\$ 86$
(b) In a sample of 20 additional households, about how many households would you expect to have monthly utility bills between $\$ 54$ and $\$ 86 ?$