Question

The mean consumption of water per household in a city was 1236 cubic feet per month. Due to a water shortage because of a drought, the city council campaigned for water use conservation by households. A few months after the campaign was started, the mean consumption of water for a sample of 97 households was found to be 1155 cubic feet per month. The population standard deviation is given to be 210 cubic feet. a. Find the p-value for the hypothesis test that the mean consumption of water per household has decreased due to the campaign by the city council. Would you reject the null hypothesis ata = 0.01? Round your answer to four decimal places. p-value- We - Hoe b. Make the test of part a using the critical value approach and a = 0.01 Round your answer for to two decimal places. Zobserved - i We Ho We conclude that the mean consumption of water per household has due to the campaign by the city council

Answer 1

Given Sample size n=97 Flean M = 1236 ž= 1155 Standard deviction = 210 d=0.01 df = noi - 96 typo thesis Test Ho: M = 1236 HI: M> 1236 Test Statistics 2= X-M stoso 1155-1236 81 210 21.32 3.790 1 215 -3.990 - table we can find p-value By using 2) P(Z > -3.19) 2 The p-value is 0.000075. Means p < 0.01 that we the nult Hypothesis to reject can - so By using a bit the critical value of ra is =) Tanat =) 20.01 096) = 2.326 121 & 24 (it is left We fail to reject the Hypothesis. Tailed) nell