Edexcel S3 2021 June — Question 3

Exam BoardEdexcel
ModuleS3 (Statistics 3)
Year2021
SessionJune
TopicCentral limit theorem
TypeConfidence interval interpretation

  1. Components are manufactured such that their length in mm is normally distributed with mean \(\mu\) and variance \(\sigma ^ { 2 }\). Below is a 95\% confidence interval for \(\mu\) calculated from a random sample of components.
    (11.52, 13.75)
Using the same random sample,
  1. find a \(90 \%\) confidence interval for \(\mu\). Four 90\% confidence intervals are found from independent random samples.
  2. Calculate the probability that only 3 of these 4 intervals will contain \(\mu\).