A new innovation product of the paper shredder machine has a long mean life time with standard deviation of 0.97. The supplier bought 50 paper shredders and distributed them to 10 faculties at a private university in Selangor subjecting to investigate the actual mean lifetime of the paper shredders. After several years, he had received complaints from faculty that the sample mean life time of the shredder machine was five years.

(i) Determine the type of test that can be used in this study. [1 mark]

(ii) The manufacturing company claims that their product of paper shredder has mean life time of more than seven years. Can you support the company's claim? Explain your conclusion using 5% significance level.