Which of the following can get in the way of concluding a causal ...

[jman1234]

Which of the following can get in the way of concluding a causal connection between two measurement variables?
 a. A weak correlation.
  b. An observational study.
  c. Confounding variables.
  d. All of the above.

Question 2

Researchers noticed that happier heart patients are much more likely to still be alive 10 years down the road than unhappy heart patients. Does this mean that if an unhappy heart patient suddenly decides to start being happy, this will cause them to live longer?

[alexisweber49]

Answer to Question 1

D

Answer to Question 2

NO. THIS IS AN OBSERVATIONAL STUDY, NOT A CONTROLLED EXPERIMENT. MANY CONFOUNDING VARIABLES EXIST, FOR EXAMPLE, EXERCISE.