Based on a four-year (2003–2007) study of over 30,000 people who were 45+ years, where all individuals were followed up regularly for diet and health changes, researchers Tsivgoulis et al. (Neurology, 2013) reported that the Mediterranean diet was linked to better memory and cognitive skills.
a. Identify the explanatory and response variables.
b. Identify a confounding variable whose effect on memory and cognitive skills might be confounded with that of the explanatory variable identified in part (a), providing an alternative explanation for the improved memory and cognitive skills among those on the Mediterranean diet. Also, include a diagram showing how this explanation works.