The length of string in the balls of string made by a particular manufacturer has mean $\mu $m and v

Question

The length of string in the balls of string made by a particular manufacturer has mean $\mu $m and variance $27.4$ m$^{2}$. The manufacturer claims that $\mu =300$. A random sample of $100$ balls of string is taken and the sample sum (total length) is found to be $S$m. If $S=29920$, test whether this provides significant evidence, at the $3%$ level, that the manufacturer’s claim overstates the value of $\mu $. Find the set of values of $S$ (to one decimal place) for which the test concludes that the manufacturer’s claim overstates the value of $\mu $ at the $5%$ significance level. State, giving a reason, whether it is necessary for the length of string in the balls of string to have a normal distribution for the test to be valid.

Accepted Answer

Do not reject $H_0$ at 3%; $S \leq 29913.9$; CLT applies since $n = 100$ is large

N1986 P2 Q10 [Modified]

N1986 P2 Q10 [Modified]

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