The communists believed that socialism could be achieved by democratic means, and turned their backs on violent revolution and dictatorship.

What is the term used for the potential confounding variable in a time-series study in which the measuring procedures may be inadvertently changed over time?

A) measurement error B) history C) instrumentation D) attrition

In essence, President Obama did not tell the complete truth when he stated that people who already had healthcare would not see any changes or lose their doctors

Indicate whether the statement is true or false