From the question, we are informed that Martin would like to start training to run a marathon and that first week he runs a total of 15 miles.
We are further told that he would like to run 0.3 more miles each week than the week before. There, the number of miles that Martin will run the second week will be:
Correlation Coefficient: The correlation coefficient is a numerical measure that measures the strength and direction of a linear relationship between two quantitative variables.