Challenging +1.2 This is a standard two-part hypothesis testing question requiring a one-sample t-test followed by a two-sample t-test. While it involves multiple steps (calculating sample means/variances, finding test statistics, comparing to critical values), these are routine procedures for Further Maths students with no novel insight required. The question clearly signposts what to do and the calculations are straightforward from given summary statistics.
9 A gardener \(P\) claims that a new type of fruit tree produces a higher annual mass of fruit than the type that he has previously grown. The old type of tree produced 5.2 kg of fruit per tree, on average. A random sample of 10 trees of the new type is chosen. The masses, \(x \mathrm {~kg}\), of fruit produced are summarised as follows.
$$\Sigma x = 61.0 \quad \Sigma x ^ { 2 } = 384.0$$
Test, at the \(5 \%\) significance level, whether gardener \(P\) 's claim is justified, assuming a normal distribution.
Another gardener \(Q\) has his own type of fruit tree. The masses, \(y \mathrm {~kg}\), of fruit produced by a random sample of 10 trees grown by gardener \(Q\) are summarised as follows.
$$\Sigma y = 70.0 \quad \Sigma y ^ { 2 } = 500.6$$
Test, at the \(5 \%\) significance level, whether the mean mass of fruit produced by gardener \(Q\) 's trees is greater than the mean mass of fruit produced by gardener \(P\) 's trees. You may assume that both distributions are normal and you should state any additional assumption.
9 A gardener $P$ claims that a new type of fruit tree produces a higher annual mass of fruit than the type that he has previously grown. The old type of tree produced 5.2 kg of fruit per tree, on average. A random sample of 10 trees of the new type is chosen. The masses, $x \mathrm {~kg}$, of fruit produced are summarised as follows.
$$\Sigma x = 61.0 \quad \Sigma x ^ { 2 } = 384.0$$
Test, at the $5 \%$ significance level, whether gardener $P$ 's claim is justified, assuming a normal distribution.
Another gardener $Q$ has his own type of fruit tree. The masses, $y \mathrm {~kg}$, of fruit produced by a random sample of 10 trees grown by gardener $Q$ are summarised as follows.
$$\Sigma y = 70.0 \quad \Sigma y ^ { 2 } = 500.6$$
Test, at the $5 \%$ significance level, whether the mean mass of fruit produced by gardener $Q$ 's trees is greater than the mean mass of fruit produced by gardener $P$ 's trees. You may assume that both distributions are normal and you should state any additional assumption.
\hfill \mbox{\textit{CAIE FP2 2013 Q9 [14]}}