CAIE FP2 2014 June — Question 10

Exam BoardCAIE
ModuleFP2 (Further Pure Mathematics 2)
Year2014
SessionJune
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicConfidence intervals
TypeCI from raw data list
DifficultyStandard +0.3 This is a straightforward application of t-test and confidence interval formulas for small samples from a normal distribution. Students must calculate sample mean and standard deviation, then apply standard procedures with t-tables. While it requires careful arithmetic and knowledge of the t-distribution, it involves no conceptual challenges or novel problem-solving—just routine statistical inference techniques that are directly taught and practiced.
Spec5.05c Hypothesis test: normal distribution for population mean5.05d Confidence intervals: using normal distribution

10 The lengths of a random sample of eight fish of a certain species are measured, in cm, as follows. $$\begin{array} { l l l l l l l l } 17.3 & 15.8 & 18.2 & 15.6 & 16.0 & 18.8 & 15.3 & 15.0 \end{array}$$ Assuming that lengths are normally distributed,
  1. test, at the \(10 \%\) significance level, whether the population mean length of fish of this species is greater than 15.8 cm ,
  2. calculate a \(95 \%\) confidence interval for the population mean length of fish of this species.

10 The lengths of a random sample of eight fish of a certain species are measured, in cm, as follows.

$$\begin{array} { l l l l l l l l } 
17.3 & 15.8 & 18.2 & 15.6 & 16.0 & 18.8 & 15.3 & 15.0
\end{array}$$

Assuming that lengths are normally distributed,\\
(i) test, at the $10 \%$ significance level, whether the population mean length of fish of this species is greater than 15.8 cm ,\\
(ii) calculate a $95 \%$ confidence interval for the population mean length of fish of this species.

\hfill \mbox{\textit{CAIE FP2 2014 Q10}}