A random sample of 135 students enrolled in statistics units in recent semesters at Macquarie University has been selected to study use of practice quizzes and academic performance. Some of the variables recorded for each student are listed below.

Variable Description

subid Subject ID

intDom domestic or international

numQuizzes the number of practice quizzes attempted

unitMark the final unit mark

ageGroupCat the age of students

Part 1

Research question:We wish to investigate whether the age of students enrolled in statistics units in recent semesters at Macquarie University is distributed according to the table below.

the age of students | 1 (less than 19) | 2 (19-21) | 3 (22-24) | 4 (more than 24) Percentage | 10 | 40 | 30 | 20 

Please complete the following table calculating the values of A, B and C.

 | 1 (less than 19) | 2 (19-21) | 3 (22-24) | 4 (more than 24) |Total Observed Count | 38 | 31 | A=*** | 30 | 135 Expected Count | 13.5 | 54 | 40.5 | B=*** | 135 chi squared | C=*** | 0.224 | 0.15 | 0.417 |1.326 

A [integer]:Answer

B [use at least 3dp]:Answer