6 The number of computers sold per day by a shop can be modelled by the random variable \(Y\) where \(Y \sim \operatorname { Po } ( 42 )\)
6
- State the variance of \(Y\)
6
- One month ago, the shop started selling a new model of computer.
On a randomly chosen day in the last month, the shop sold 53 computers.
Carry out a hypothesis test, at the \(5 \%\) level of significance, to investigate whether the mean number of computers sold per day has increased in the last month.
[0pt]
[6 marks]
6 - Describe, in the context of the hypothesis test in part (b), what is meant by a Type II error.