Question

209 Wed 22 May 4A plant that purifies its liquid waste discharges the treated waste into a local river. An environmental protection agency inspector has collected twelve water specimens. The bacteria counts for each of the 12 specimens (6 at the discharge point of the plant and 6 at an upstream location) are reported in the following table. 30 36 Discharge at the plant 29 30 26 31 32 (a) Calculate a 90% confidence interval for the population mean of the bacteria counts at the plant discharge point. [6 marks] Continued over Calculate a 95% confidence interval for the population standard deviation of the upstream bacteria counts. [6 marks] 209 Wed 22 May

Answer 1

90% confedence herud for the Populatten mean the bacterR at the plaint di'schagerat. 20 36 33 282ר Зу 29 3D 26 3 .So ohere SAS 1 2

2. 6011-6011 . C 47.33

7 33 47-33 23.18 for 90 % So So

6 31.66 -866 1 3317 구. 09. So

Confe IACe are. 70% ‘R So กุว. リー