Idea 13of 22Builds onSplit into groups first
Every 4th name on the list
How can a list and a counting step pick a sample?
Today you'll discover
- how to step down a list
- why the start is random
- how many the step gives
Think firstPriya starts at name 3
Priya starts at name 3 and takes every 4th name. Which name comes after 3?
Decide first, then press Next. Follow the numbers above the marks, 4 at a time.
The same 60 students, each numbered 1 to 60 in reading order. Starting at 3, every 4th mark is ringed: 3, 7, 11 and on to 59, three in each row. At the right: 5 of 15 want a court; all 60 students, 18 of 60.
See the whole ideathe big idea and the key word, in one place
The big idea
Systematic random sampling picks a random start on a list, then takes every 4th name, or every 10th.
Step down the list
Start at a random place, then add the same step every time.
- start3
- +47
- +411
- +415
- … to59
Easy to get wrongWatch for a list with its own pattern. If every 4th seat is by a window, every 4th name picks only window seats.
Key word
- systematic random sampling
- choosing from a list by starting at a random place and taking every 4th, 10th or other name
Ready to use it?
- Name systematic random sampling from a description.
- List the names a step picks.