Correlation Coefficient is an important statistical concept which quantitatively measures the strength of the relationship between two variables. It is a number that is always between -1 and 1, where the -1 or 1 value indicates a perfectly linear inverse or positive relationship, respectively. That is, one variable increases or decreases in direct proportion to the other variable. If the correlation coefficient is close to 0, then there is no linear association between the two variables.

Correlation coefficients enable us to demonstrate the strength of an association between pairs of variables. In practice, correlation coefficients can be used to understand the relationship between two variables in a variety of applications. For instance, in market research, a correlation coefficient may be employed to examine the level of customer satisfaction for a product versus the sales trend for that product. The strength which the correlation coefficient yields can show us how powerfully the two chosen variables are connecting.

The Pearson correlation coefficient is the most common type of correlation coefficient, as it measures the strength and the direction of relationships between two variables. The statistical significance of a correlation can be calculated from the correlation coefficient and the number of data points in the sample, given that the data is normally distributed. In addition, it should be taken into account that the values required to signal a meaningful relationship depends on the particular application.

In conclusion, correlation coefficients are widely used to measure the strength of the relationship between two variables, as they can give us insight into the power of the linear association between them. The Pearson correlation coefficient is the most frequently used type of correlation coefficient and the values required to signal a meaningful association will depend on the application in question. Ultimately, the correlation coefficient helps us to better understand the linear relationships between two variables, no matter what the application may be.