Calculate Pearson’s correlation coefficient, 𝑟, from raw data using technology, and interpret it to quantify the strength of a linear association.

A marine biologist is investigating whether the salinity level (parts per thousand, ppt) of coastal water influences the population density of barnacles (number per square metre). Data were collected from seven sampling sites along a coastline. Calculate Pearson's correlation coefficient for the dataset and interpret the value to describe the strength of the linear association between salinity and barnacle population density.

Calculate Pearson's correlation coefficient, $r$, for the data shown in the table below and use it to describe the strength of the linear association between weekly exercise time and resting heart rate.

A researcher collected data on the relationship between hours spent studying per week and performance on a standardized test (out of 100) for 12 students. The Pearson correlation coefficient calculated from this dataset is $r = -0.14$. Which statement best describes the strength and direction of the association between study hours and test performance?