AS Paper 2: Statistics and Mechanics

Paper 2: Statistics and Mechanics AS Wednesday 22 May 2019 SECTION A: STATISTICS 1. A sixth form college has 84 students in Year 12 and 56 students in Year 13 The head teacher selects a stratified sample of 40 students, stratified by year group. (a) Describe how this sample could be taken. (3) The head teacher is investigating the relationship between the amount of sleep, s hours, that each student had the night before they took an aptitude test and their performance in the test, p marks. For the sample of 40 students, he finds the equation of the regression line of p on s to be p = 26.1 + 5.60s (b) With reference to this equation, describe the effect that an extra 0.5 hours of sleep may have, on average, on a student’s performance in the aptitude test. (1) (c) Describe one limitation of this regression model. (1) (Total for Question 1 is 5 marks) ___________________________________________________________________________ 2. The Venn diagram shows three events, A, B and C, and their associated probabilities. Events B and C are mutually exclusive. Events A and C are independent. Showing your working, find the value of x, the value of y and the value of z. (5) (Total for Question 2 is 5 marks)