Does delaying oral practice hinder learning a foreign language? Researchers randomly assigned25beginning students of Russian to begin speaking practice immediately and another25to delay speaking for 4 weeks. At the end of the semester both groups took a standard test of comprehension of spoken Russian. Suppose that in the population of all beginning students, the test scores for early speaking vary according to theN(35,8) distribution and scores for delayed speaking have theN(31,6) distribution.

If the experiment were repeated many times, what would be the sampling distribution of the differencey-xbetween the mean scores in the two groups? (Round your answer forsto two decimal places.)