Item A: A form class in a mixed secondary school. The form tutor, Ms Khan, has been told by senior staff that three pupils, Amir (working-class), Chloe (middle-class) and Yusuf (working-class), have been placed on the same 'target' band. Ms Khan believes Amir and Yusuf are 'likely to struggle' because of their background and so gives them shorter, simpler classroom tasks, checking them more often. Chloe receives extended, open-ended tasks and positive, detailed feedback. After a term, Chloe's test scores improved by two grades on average, while Amir and Yusuf improved by half a grade. Using Item A and your sociological knowledge, explain one reason why teacher expectations in Item A may have affected Amir's and Yusuf's achievement.
(Total for Question 7 is 4 marks)