The mean and standard deviation of domestic water bills among 250

residents were RM25.50 and RM5.30, respectively. Use this data to

respond to the following questions:

a. What are the probabilities that a randomly selected domestic water bill

among 250 residents was:

i. more than RM35.00?

ii. less than RM20.00?

iii. between RM25.00 and RM40.00?

b.

How many residents pay more than RM30.00 for their domestic water

bill?

c.

What is the amount for the 95% confidence interval of the domestic

water bills?