Scientists studying a particular species of endangered primate are concerned that the health of the primates is in danger due to habitat loss and malnutrition. Even a slight decrease in average body weight is of great concern. Over the summer, each of the 334 remaining members of the species were examined, and general information was recorded such as weight. The average weight was 215 pounds, with a standard deviation of 20. Rather than disturb all 334 primates again so shortly since the last examination, the decision is made to randomly select a sample of 6. Their weight values were as follows: 200, 180, 172, 190, 180, 163.
What is the research and null hypothesis and why?