Explain what is meant by a correlation; give a couple of examples

What will be an ideal response?

Answer:
A correlation is a statistical indication of how strongly two variables are related. A correlation between two variables can range from -1.0 to +1.0. A correlation of 0 indicates that there is no relationship between two variables, while a correlation closer to -1.0 or +1.0 indicates a stronger relationship. More specifically, a positive correlation (greater than 0) indicates that, as values for one variable increase, so do values for the other variable. A negative correlation (less than 0) indicates that as values for one variable increase values for the other variable decrease. So, for example, attractiveness is positively correlated with dating activity (as attractiveness levels increase, people tend to date more), while football-team errors are negatively correlated with winning (as numbers of errors (interceptions, fumbled tackles) increase, the ratio of wins to losses decreases. Although extremely useful for making predictions, correlations by themselves cannot be used as indicators of causality (although it is tempting to make a causal connection between mistakes on the football field and losing football games!).