Hw a researcher in the field of sports biomechanics believes he has found the “ideal” running posture for sprinters. he selects a random sample of 12 high school track sprinters and records their best 200 m time (in seconds). then he trains these sprinters over several days to run using his proposed “ideal” posture. in the days after the training ends, these sprinters run several 200 m races, and the researcher records their best performance from this time period. the before-training and after-training times (in seconds) are given below. use the sign test to test the claim that the proposed ideal running posture is effective (i. e. the median of the “before – after” differences is positive). use a 0.05 level of significance.