Example 1.22 from Statistics, 1.4 Experimental Design and Ethics

Experimental Design and Ethics: example 1.22

A researcher wants to study the effects of birth order on personality. Explain why this study could not be conducted as a randomized experiment. What is the main problem in a study that cannot be designed as a randomized experiment?

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Solution
The explanatory variable is birth order. You cannot randomly assign a person’s birth order. Random assignment eliminates the impact of lurking variables. When you cannot assign subjects to treatment groups at random, there will be differences between the groups other than the explanatory variable.

How did it go?

Solution

Solution