6 Gordon is a cricketer. Over a long period he knows that his population mean score, in number of runs per innings, is 28 , and the population standard deviation is 12 . In a new season he adopts a different batting style and he finds that in 30 innings using this style his mean score is 28.98 .
- Stating a necessary assumption, test at the \(5 \%\) significance level whether his population mean score has increased.
- Explain whether it was necessary to use the Central Limit Theorem in part (i).