1 Press Ctrl-A ©G Dear2009 – Not to be sold/Free to use Types of Sample Stage 6 - Year 11 Applied Mathematic (Preliminary General 1)

2 Every member of the population has an equal chance of being chosen. Chance is the only factor involved in selecting elements of the sample Names drawn from a hat. JohnMary Or use the Random Number Generator on your calculator

3 Example We have 825 students at our high school. They are numbered from 1 to 825. We need to pick 3 students at random. Use your calculator to get 3 random numbers ,0.976,0.251, Student 1 = 0.453x 825= 374 Student 2 = 0.976x 825= 805 Student 3 = 0.251x 825= 207

4 Deliberately choose people who are representative of the whole population. In a school population we have six groups. Year 7,Year 8,Year 9, Year 10,Year 11, Year 12. Each group should numerically represent their fraction of the population.

5 Example We have 825 students at our high school. Year 7 =135Year 8 = 160Year 9 = 150 Year 10=150Year 11=120Year 12=110 We want to survey 50 students How many are chosen from each year? Year 7 = x 50 = 8Year 8 = x 50= 10 Year 9 = x 50 = 9Year 10 = x 50= 9 Year 11 = x 50 = 7Year 12 = x 50= =50

6 Choose people using some systematic or organised method. Often used in quality control. Check every 10 th pair of shoes for quality. Check Continue Check