AQA S3 2009 June — Question 1

Exam BoardAQA
ModuleS3 (Statistics 3)
Year2009
SessionJune
TopicLinear combinations of normal random variables
TypeConfidence interval for difference of proportions

1 An analysis of a random sample of 150 urban dwellings for sale showed that 102 are semi-detached. An analysis of an independent random sample of 80 rural dwellings for sale showed that 36 are semi-detached.
  1. Construct an approximate \(99 \%\) confidence interval for the difference between the proportion of urban dwellings for sale that are semi-detached and the proportion of rural dwellings for sale that are semi-detached.
  2. Hence comment on the claim that there is no difference between these two proportions.