[Solved] A basic reason for the existence of so many interest groups in the United States is A)the American tradition of free association. B)the extent of diverse interests in American society. C)America's federal system of government. D)the separation of powers in American government. E)All of these answers are correct. P-Value: The p-value is a measure in statistical hypothesis testing representing the probability of obtaining a result at least as extreme as the observed one, assuming the null hypothesis is true. Hypothesized Mean Difference: The presumed difference between the means of two populations or conditions being compared in a statistical hypothesis test. Two-Tail: A term used in statistics referring to the two-tailed test of significance that checks for the possibility of positive or negative differences. Observations: The act of noting and recording something with instruments or the naked eye as part of a scientific or empirical study.