Answer:
The percentage of the bank's customers carry daily balances between $700 and $1,000 is 65.7%.
The minimum daily balance on which it should be willing to pay interest is $1,198.
Step-by-step explanation:
We have a normal distribution with mean = $800 and standard deviation = $150.
a) We can calculate this value with the standard normal distribution, calculating the z-value for $700 and $1,000.
The percentage of the bank's customers carry daily balances between $700 and $1,000 is 65.7%.
b) We must calculate from what amount only 6% of the accounts remain.
This is done by solving:
This happens for a z-value of z=2.652.
This corresponds to a amount of $1,198.
The minimum daily balance on which it should be willing to pay interest is $1,198.