Week 8 Assignment: Correlation and Causation

Week 8 Assignment: Correlation and Causation Understand the difference between correlation and causation Question True or False: The more samples taken in a scientific study, the longer the amount of time it will take to complete the research on the samples. Although there are other factors that affect study time, such as experience and equipment, increasing the number of samples will cause an increase in research time. Correct! You nailed it. Understand the difference between correlation and causation Question Suppose that a large controlled experiment tests whether caffeine improves reaction times. A very large number of randomly selected participants are randomly given identical-seeming pills with varying doses of caffeine (including none) and then given tests of reaction times under the same conditions. The experiment finds a strong negative correlation between caffeine dose and reaction time. (Note that lower reaction times are better.) Correct answer: There is evidence that caffeine causes lower (better) reaction times. Correlation alone does not prove causation, but this scenario provides more evidence than just correlation between two variables. Since the data were obtained from an appropriately randomized controlled experiment, a correlation can be used as evidence of a causal relationship. Since all other variables were controlled, there is no third variable that could be associated with caffeine that actually causes differences in reaction times. Yes that's right. Keep it up! Interpret the slope and y-intercept of the least squares regression line