Page 3 of 6

Section 3 of 6 (9 + 9 = 18 Marks/Points)

Question 7 (9 points)

The following summary measures describe the monthly amount Australians are willing to pay in order to have completely renewable energy as their electricity supply. This information has been gathered from the sample of 40 Australian residents.

Monthly_Payment ($)
Mean	145
Standard Error	16
Median	80
Mode	0
Standard Deviation	101
Sample Variance	10240
Skewness	1.21
Range	500
Minimum	0
Maximum	500
Sum	5800
Count	40

Complete the following tasks using the above summary measures.

1. 1. Construct a 90% confidence interval of the Monthly_Payment amount Australians would be prepared to pay for electricity that was sourced form a totally renewable energy source. Show your calculations.
   2. Provide a plain language interpretation of the interval you constructed in part i.
   3. The Energy Council of Australia (ECA) have calculated the current average monthly electricity bill in Australia at $130. Is there any evidence to suggest that the amount Australians are willing to pay in order to have completely renewable energy as their electricity supply is more than the amount they currently pay on average? Explain your reasoning. (No calculations required)