Investigators planted pine seedlings in a greenhouse in either full light or light reduced to 5% of normal by shade cloth to determine how well these pines grow in shade. At the end of the study, they dried the young trees and weighed them.
I. What is the population?
II. What is the sample?
III. Is the study observational or experimental? Justify your answer.
IV. If observational, identify ALL variables. If experimental, identify ALL independent and dependent variables.
V. For each of the variables identified in part IV, list which of the four levels/scales of measurement was used to obtain data on these variables?
VI. Classify each of the variables identified in part IV as either attribute or numerical.