Ability to grow in shade may help pines found in the dry for

Ability to grow in shade may help pines found in the dry forests of Arizona resist drought. To test this hypothesis, investigators planted pine seedlings in a greenhouse in either full light, light reduced to 25% of normal, or light reduced to 5% of normal. At the end of the study, they dried the young trees and weighed them.

This is an example of

A. stratified observational study.

B. matched pairs experiment.

C. completely randomized experiment.

D. block experiment.

Solution

Answer to the question)

Since in this case three different treatments are provided

this results in the creation of blocks

This is called Blocked experiment

thus option D is the correct answer