WJEC Further Unit 2 2018 June — Question 6

Exam BoardWJEC
ModuleFurther Unit 2 (Further Unit 2)
Year2018
SessionJune
TopicChi-squared distribution

6. A student, considering options for the future, collects data on education and salary. The table below shows the highest level of education attained and the salary bracket of a random sample of 664 people.
Fewer than 5 GCSE5 or more GCSE3 A LevelsUniversity degreePost graduate qualificationTotal
Less than £200001832202810108
£20000 to £60000509511215550462
More than £600003222935594
Total7114916121865664
By conducting a chi-squared test for independence, the student investigates the relationship between the highest level of education attained and the salary earned.
  1. State the null and alternative hypotheses.
  2. The table below shows the expected values. Calculate the value of \(k\).
    Expected valuesFewer than 5 GCSE5 or more GCSE3 A LevelsUniversity degreePost graduate qualification
    Less than £20000\(k\)24.2326•1935.4610.57
    £20000 to £6000049.40103.67112.02151.68\(45 \cdot 23\)
    More than £6000010.0521.09\(22 \cdot 79\)30.869.20
  3. The following computer output is obtained. Calculate the values of \(m\) and \(n\).
    Chi Squared ContributionsFewer than 5 GCSE5 or more GCSE3 A LevelsUniversity degreePost graduate qualification
    Less than £200003.604530799\(m\)1.461651.56860.03098
    £20000 to £600000.0072727350.725354E-060.072640.50396
    More than £60000\(4 \cdot 946619863\)0.03897169081\(0 \cdot 55498\)\(n\)
    X-squared \(= 19 \cdot 61301 , d f = 8 , p\)-value \(= 0 \cdot 0119\)
    1. Without carrying out any further calculations, explain how X-squared \(= 19 \cdot 61301\) (the \(\chi ^ { 2 }\) test statistic) was calculated.
    2. Comment on the values in the "Fewer than 5 GCSE" column of the table in part (c).
  4. The student says that the highest levels of education lead to the highest paying jobs. Comment on the accuracy of the student's statement.