Statistics 528 - Lecture 12
1
Statistics 528 - Lecture 12
Prof. Kate Calder
1
Randomization
How do we randomly assign the experimental units or subjects to the
different treatment groups.
Idea:
“draw names out of a hat”
In practice,
1. Use a random number tables.
2. Use statistical software.
Statistics 528 - Lecture 12
Prof. Kate Calder
2
A
table of random digits
is a list of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, that has
the following properties:
1. The digit in any position in the list has the same chance of being any one of
0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
2. The digits in different positions are independent in the sense that the value
of one has no influence on the value of the other.
As a result,
•
Any
pair
of random digits has the same chance of being any of the
100 pairs: 00, 01, 02, …, 98, 99.
•
Any
triple
of random digits has the same chance of being any of the
1000 triples: 000, 001, 002, …, 998, 999.
•
Any so on…