Which of the following cannot be obtained from observational studies?
a. Definitive evidence of a causal connection.
b. A reasonable explanation for a causal connection.
c. Any evidence of a causal connection.
d. Definitive evidence of a correlation.
Question 2
Suppose you heard on the radio that women who overuse antibiotics have a higher chance of developing breast cancer. You look into the literature on this, and find ten observational studies done by different researchers under different conditions, all of which confirm the results that you heard on the radio. What do you conclude?
a. The evidence for a causal connection between overuse of antibiotics and increased risk of breast cancer is strengthened by these varying studies.
b. These studies have too many different confounding variables that together weaken the evidence for a causal connection.
c. Since the studies were all done under different conditions, there is not enough information to make a conclusion.
d. None of the above.
Experimental Evidence for Infrared Radiation
Evidence of Water on Mars
Microbes that have become model organisms for genetic studies
Heritability of several addictive behavioral disorders derived from twin studies
Experimental evidence of cytoplasmic localization in an amphibian oocyte.
Evidence of lethal mutations in plants