A random sample of 50 Canadians were asked to supply two pieces of information: the number of hours of sleep they get on a typical week night and their level of stress on a five-point likert rating scale (very stressed, stressed, ... very unstressed). What is the next step in determining if there is a linear relationship between the two variables?

a) Bartlett's test

b) Pearson's Correlation test

c) Anderson-Darling test

d) Spearman's Correlation test

e) Kruskal-Wallis test