Which correlation coefficient represents the weakest relationship?

For people to decide about participating in psychological research, they must be given full knowledge of the nature of the study and their rights. This principle is called:

Fogel was also responsible for bringing the Body Mass Index (BMI) to the forefront of economic theories of population.  Fogel found that the better people ate, all of the following occurred  EXCEPT:   

Those 16 years of age and older who are either working or looking for work

The purchase of new plants, new equipment, new buildings, and new residences, plus net additions to inventories

44. Unemployment that occurs because job seekers and employers need time to find each other  

Worker productivity depends on all of the following EXCEPT:

When a nation is in the early stages of economic development, it is wise for that nation to invest its money in       

64. In the above graph, we can see that the Great Depression caused a 

Unemployment that fluctuates with the business cycle, increasing during contractions and decreasing during expansions