A teacher, Mr. Ku, suspects that the average time a student spends on his or her mobile phone per da

Question

A teacher, Mr. Ku, suspects that the average time a student spends on his or her mobile phone per day is ${{\mu }_{0}}$ minutes. He selected a random sample of $97$ students in the school who own mobile phones and recorded the amount of time each student spent on his or her phone in a randomly selected day. The results are displayed in the table below. Calculate unbiased estimates of the population mean and variance of the time a student spends on his or her mobile phone per day. [2] The null hypothesis that the average time a student spends on his or her mobile phone per day is ${{\mu }_{0}}$ minutes is tested, at $5\%$ level of significance, against the alternative hypothesis that the average time a student spends on his or her mobile phone per day differs from ${{\mu }_{0}}$ minutes. Determine the range of values of ${{\mu }_{0}}$ for which the null hypothesis is rejected. [5] Explain, in the context of this question, the meaning of ‘at $5\%$ level of significance’. [1] If the null hypothesis in (ii) is rejected at $5\%$ significance level, can we reject the null hypothesis at $1\%$ level of significance? Explain your answer. [1]

Accepted Answer

Inconclusive

2018 EJC P2 Q8

2018 EJC P2 Q8

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