AQA S2 2007 June — Question 8

Exam BoardAQA
ModuleS2 (Statistics 2)
Year2007
SessionJune
TopicHypothesis test of a normal distribution

8 A jam producer claims that the mean weight of jam in a jar is 230 grams.
  1. A random sample of 8 jars is selected and the weight of jam in each jar is determined. The results, in grams, are $$\begin{array} { l l l l l l l l } 220 & 228 & 232 & 219 & 221 & 223 & 230 & 229 \end{array}$$ Assuming that the weight of jam in a jar is normally distributed, test, at the \(5 \%\) level of significance, the jam producer's claim.
  2. It is later discovered that the mean weight of jam in a jar is indeed 230 grams. Indicate whether a Type I error, a Type II error or neither has occurred in carrying out the hypothesis test in part (a). Give a reason for your answer.