Learning a foreign language. Does delaying oral practice hinder learning a foreign language? Researchers randomly assigned 25 beginning students of Russian to begin speaking practice immediately and another 25 to delay speaking for four 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 the N132, 62 distribution and scores for delayed speaking have the N129, 52 distribution. (a) What is the sampling distribution of the mean score x in the early-speaking group in many repetitions of the experiment? What is the sampling distribution of the mean score y in the delayed-speaking group? (b) If the experiment were repeated many times, what would be the sampling distribution of the difference y x between the mean scores in the two groups? (c) What is the probability that the experiment will find (misleadingly) that the mean score for delayed speaking is at least as large as that for early speaking?

Assignment # 5 STA 5205, 5126 and 4202 Date: Monday, November 30, 2015 This assignment is based on Chapter 7 and 13. You must show all necessary work to get full credit. Please submit your assignment in due time. Some selected questions will be graded. Pl keep 1” margin in all sides of the paper. You must define both null and alternative hypotheses for any test related question. You may use any computer software unless oherwise stated. First page is your cover page. First & Last Name:----------------------------------Panther ID:------------------------------------------- Problem #1: A router is used to cut locating notches on a printed circuit board. The vibration level at the surface of the board