Edexcel S3 — Question 4

Exam BoardEdexcel
ModuleS3 (Statistics 3)
TopicChi-squared distribution

4. A paranormal investigator invites couples who believe they have a telepathic connection to participate in a trial. With each couple one person looks at a card with one of five shapes on it and the other person says which of the shapes they think it is. This is repeated six times and the number of correct answers recorded. The results from 120 couples are given below.
Number Correct0123456
Number of Couples2656288200
The investigator wishes to see if this data fits a binomial distribution with parameters \(n = 6\) and \(p = \frac { 1 } { 5 }\) and calculates to 2 decimal places the expected frequencies given below.
Number Correct0123456
Expected Frequency9.831.840.180.01
  1. Find the other expected frequencies.
  2. Stating your hypotheses clearly, test at the \(5 \%\) level of significance whether or not the distribution is an appropriate model.
  3. Comment on your findings.