Suppose a sample of 49 paired differences that have been randomly selected from a normally distributed population of paired (a) Calculate a 95 percent confidence interval for d=12. (Round your answers to 2 decimal places.) (b) Test the null hypothesis H0:d=0 versus the alternative hypothesis Ha:d=0 by setting a equal to .10,.05,.01, and .001 . How much evidence is there that d differs from 0