Question: based on a recent study the monthly utility bills for...
Based on a recent study, the monthly utility bills for three-room flats in Singapore can be assumed to be normally distributed with mean $135 and standard deviation $42.
If a household living in a three-room flat is randomly selected,
i. What is the probability that its utility bill is more than $155 [3 marks]
ii. What is the probability that its utility bill is between $129 and $165? [4 marks]
iii. If 20% of the utility bills for households living in three-room flats are above a certain value V, find the value of V. [5 marks]