Aswine producer wants to know if the average weight of his pigs is different from the breed average of 230 lb. he selects a random sample of 16 weights from pigs in his herd and calculates a sample mean of 220 lb and a sample standard deviation of 25 lb. assume that he wants to detect departure from 230 lb in either direction and that he uses a significance level of 0.10. calculate the value of the test statistic needed to test the null hypothesis.