An observational study found that the amount of sleep an employee gets each night is associated with job performance. The correl
ation coefficient was found to be r=0.86. A reader of the study concluded that more sleep causes employees to perform better. Why is such a conclusion not correct? A)The correlation value should equal 1 for such a conclusion.
B)The correlation value should be negative for such a conclusion.
C)The sample was not representative of the population.
D) Causation cannot be determined from an observational study.
E) The correlation value implies that less than 75% of the variability in job performance can be explained by sleep.
