Part (A) [3 MARKS]

With regards to hypothesis testing, for each of the following, draw a normal distribution curve to represent the rejection area:

(a)Two-tailed test. (1 mark)

(b)Upper-tailed test. (1 mark)

(c)Lower-tailed test. (1 mark)

Part (B) [12 MARKS]

An environmental researcher claims that the mean time that an adult can stay under the ice, below -50 degrees, without any food or drink is at least 6 hours. To prove his claim, he administers a test to 16 randomly adults. The standard deviation chosen is 4, the average time is 3, and a is set at 0.10. Based on this information, you are required to perform the following:

(a)Draw a graph to show clearly, the rejection, acceptance and the critical value of Z. (3 marks)

(b)Use a 'Z Test' approach to test whether the researcher's claim is likely to be true or not. (6 marks)

(c)Alternatively, use the p-value approach to test the above hypothesis. (3 marks)