CAIE S2 2015 June — Question 5

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2015
SessionJune
TopicHypothesis test of a normal distribution

5 The volumes, \(v\) millilitres, of juice in a random sample of 50 bottles of Cooljoos are measured and summarised as follows. $$n = 50 \quad \Sigma v = 14800 \quad \Sigma v ^ { 2 } = 4390000$$
  1. Find unbiased estimates of the population mean and variance.
  2. An \(\alpha \%\) confidence interval for the population mean, based on this sample, is found to have a width of 5.45 millilitres. Find \(\alpha\). Four random samples of size 10 are taken and a \(96 \%\) confidence interval for the population mean is found from each sample.
  3. Find the probability that these 4 confidence intervals all include the true value of the population mean.