- 20 Marks
Question
A research was conducted to know the average monthly household expenditure on mobile phones in DETOTAR Estate.
The research shows the average monthly household expenditure to be N5,200. Assume that the monthly household expenditure on mobile phones in the Estate is normally distributed with a standard deviation of N1,800. Determine the probability of a randomly selected household in DETOTAR Estate if the monthly expenditure on mobile phone is:
a. more than N8,700 (5 Marks)
b. between N2,600 and N9,000 (6 Marks)
c. between N7,600 and N10,200 (6 Marks)
d. less than N8,800 (3 Marks)
Answer
a) Required probability (shaded area) is
0.5 – 0.4738 = 0.026
b) Required probability (shaded area) is
c) Required probability (shaded area) is
d) Required probability (shaded area) is
Summary of Answers:
- a. More than N8,700: 0.0256
- b. Between N2,600 and N9,000: 0.9081
- c. Between N7,600 and N10,200: 0.0890
- d. Less than N8,800: 0.9772
- Tags: Household Expenditure, Normal distribution, Probability
- Level: Level 1
- Series: MAY 2015
- Uploader: Kwame Aikins