Accounting Water usage is closely watched in many parts of Australia. Suppose that in a summer the average household usage in Hobart is 408 litres per day. A year later it examines records of a sample of 50 households and finds that there is a daily mean usage of 380 litres with a standard deviation of 25 litres. a.Do you think the average daily water usage has been changed in the second summer? Use the 5% level of significance level for hypothesis testing. b.Because of the draught situation in Australia, after the first summer, the price of water in Hobart was increased to encourage households to reduce their water consumption. How do you evaluate the effect of increasing water prices? Use the 5% level of significance level for hypothesis testing.