AQA S2 2014 June — Question 1 7 marks

Exam BoardAQA
ModuleS2 (Statistics 2)
Year2014
SessionJune
Marks7
TopicHypothesis test of a normal distribution

1 Vanya collected five samples of air and measured the carbon dioxide content of each sample, in parts per million by volume (ppmv). The results were as follows. $$\begin{array} { l l l l l } 387 & 375 & 382 & 379 & 381 \end{array}$$
  1. Assuming that these data form a random sample from a normal distribution with mean \(\mu\) ppmv, construct a \(90 \%\) confidence interval for \(\mu\).
    [0pt] [6 marks]
  2. Vanya repeated her sampling procedure on each of 30 days and, for each day's results, a \(90 \%\) confidence interval for \(\mu\) was constructed. On how many of these 30 days would you expect \(\mu\) to lie outside that day's confidence interval?
    [0pt] [1 mark]