| Exam Board | CAIE |
| Module | FP2 (Further Pure Mathematics 2) |
| Year | 2014 |
| Session | November |
| Topic | Hypothesis test of a normal distribution |
Fish of a certain species live in two separate lakes, \(A\) and \(B\). A zoologist claims that the mean length of fish in \(A\) is greater than the mean length of fish in \(B\). To test his claim, he catches a random sample of 8 fish from \(A\) and a random sample of 6 fish from \(B\). The lengths of the 8 fish from \(A\), in appropriate units, are as follows.
$$\begin{array} { l l l l l l l l }
15.3 & 12.0 & 15.1 & 11.2 & 14.4 & 13.8 & 12.4 & 11.8
\end{array}$$
Assuming a normal distribution, find a \(95 \%\) confidence interval for the mean length of fish in \(A\).
The lengths of the 6 fish from \(B\), in the same units, are as follows.
$$\begin{array} { l l l l l l }
15.0 & 10.7 & 13.6 & 12.4 & 11.6 & 12.6
\end{array}$$
Stating any assumptions that you make, test at the \(5 \%\) significance level whether the mean length of fish in \(A\) is greater than the mean length of fish in \(B\).
Calculate a 95\% confidence interval for the difference in the mean lengths of fish from \(A\) and from \(B\).