During the Gulf War, a Government Official Claimed That the Average

Essay

During the Gulf War, a government official claimed that the average car owner refilled the fuel tank when there was more than 3 litres of petrol left. To check the claim, 10 cars were surveyed as they entered a service station. The amount of petrol (in litres) was measured and recorded as shown below. $\begin{array}{|r|r|r|r|r|r|r|r|r|r|}\hline3&5&3&2&3&3&2&6&4&1\\\hline\end{array}$ Assume that the amount of petrol remaining in the tanks is normally distributed with a standard deviation of 1 litre.
Can we conclude at the 10% significance level that the official was correct?