Which of the following is both a necessary and a sufficient ...

[Zoey63294]

Which of the following is both a necessary and a sufficient principle to prove a causal relationship?
 
  a. Where there is the effect, there must also be the cause.
  b. Where there is no cause, there should be no effect.
  c. Where there is a change made in the cause, there should be a resulting change in the effect.
  d. All of these are necessary and sufficient conditions for proving a causal relationship between variables.

Question 2

The operational definition for the independent variable in an experiment specifies how the variable _____.
 
  a. is measured c. is controlled
  b. is manipulated d. is analyzed

[Sammyo]

Answer to Question 1

C
The first two principles are true for events that are correlated but not causally related. They are necessary but not sufficient for proving causality.

Answer to Question 2

A
The independent variable is manipulated by the experimenter. The operational definition specifies exactly how the manipulation was accomplished.

[Zoey63294]

TYSM

[Dinolord]

Excellent