Chapter 54

Calculate 95\% confidence limits. What are the \(95 \%\) confidence limits of a sample with a mean \(=24.7\), standard deviation \(=6.8\) and number of data values \(=16 ?\) (Express your answer to three significant figures.)

Practise using a \(t\)-test. chemistry student measures the paracetamol concentration (mg \(\mathrm{g}^{-1}\) ) in tablets by two different analytical methods. Seven tablets from different batches were analysed to see whether the results obtained by the two methods differed. Carry out a \(t\)-test on the data and draw appropriate conclusions. Paracetamol concentration \(\left(\mathrm{mg} \mathrm{g}^{-1}\right)\) $$ \begin{array}{|l|c|c|c|c|c|c|c|} \hline \text { Method 1 } & 7.5 & 8.1 & 7.6 & 6.2 & 7.5 & 7.8 & 8.9 \\ \hline \text { Method 2 } & 5.6 & 7.5 & 8.2 & 6.7 & 3.5 & 6.5 & 5.9 \\ \hline \end{array} $$