The batteries, used in a particular model of mobile phone, is advertised as having a ‘talk-time’ of \(5\) hours. In a test at the \(5\)% level of significance, it is found that the population mean talk-time is less than \(5\) hours. Using only this information, and giving a reason in each case, state whether each of the following statements is (i) necessarily true, (ii) necessarily false, or (iii) neither necessarily true or necessarily false.


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