Moderate -0.3 This is a straightforward two-tailed t-test with clearly stated hypotheses (H₀: μ = 101.2 vs H₁: μ ≠ 101.2). Students must calculate sample mean and standard deviation from summations, then apply the standard t-test procedure. While it requires multiple computational steps and understanding of hypothesis testing, it's a routine S4 question with no conceptual surprises—slightly easier than average due to its textbook structure.
Historical records from a large colony of squirrels show that the weight of squirrels is normally distributed with a mean of 101.2 g. Following a change in the diet of squirrels, a biologist is interested in whether or not the mean weight has changed.
A random sample of 14 squirrels is weighed and their weights \(x\), in grams, recorded. The results are summarised as follows:
\(\sum x = 1370\), \(\sum x^2 = 134487.50\).
Stating your hypotheses clearly test, at the 5\% level of significance, whether or not there has been a change in the mean weight of the squirrels. [7]
Historical records from a large colony of squirrels show that the weight of squirrels is normally distributed with a mean of 101.2 g. Following a change in the diet of squirrels, a biologist is interested in whether or not the mean weight has changed.
A random sample of 14 squirrels is weighed and their weights $x$, in grams, recorded. The results are summarised as follows:
$\sum x = 1370$, $\sum x^2 = 134487.50$.
Stating your hypotheses clearly test, at the 5\% level of significance, whether or not there has been a change in the mean weight of the squirrels. [7]
\hfill \mbox{\textit{Edexcel S4 Q1 [7]}}