Workers on a production line produce an average of 67 or more faulty items per shift. A training package has been developed and tested on a random sample of 16 workers, found that the mean number of faulty items was 65 with a variance of 16 items. Based on the sample results can we conclude that the workers performance had improved? Page 17 of 18 Assume that faulty items are approximately normally distributed, test at 1 % level of significance