Marine biologists are studying a major reduction in the number of shrimp and commercial fish in the Gulf of Mexico. The area in which the Mississippi River enters the gulf is one of the areas of greatest concern. The biologists hypothesize that nutrient-rich water, including mainly nitrogens from the farmlands of the Midwest, flows into the gulf, which results in rapid growth in algae that feeds zooplankton. Bacteria then feed on the zooplankton pellets and dead algae, resulting in a depletion of the oxygen in the water. The more mobile marine life flees these regions while the less mobile marine life dies from hypoxia. To monitor this condition, the mean dissolved oxygen contents (in ppm) of four areas at increasing distance from the mouth of the Mississippi were determined. There is a single factor in this study, and that is distance. The four distance levels are A = 1km, B = 5km, C = 10km, and D = 20km. A random sample of 10 water samples were taken at a depth of 12 meters in each of the four areas. The sample data can be imported using the code below. The biologists claim that the true oxygen content is lower in the areas closer to the mouth of the Mississippi. Use the appropriate tests to see if there is a difference in the oxygen content between these distances and determine if the biologists claim is true

OxyCont=read.csv('https://www.dropbox.com/s/rlieq8oegsyadxr/Mississippi.txt?dl=1',header=T,sep=',')

What type of test are we doing in Rstudio?