A. For each of the problem given below, state null and alternative hypothesis in words and in symbols. 1. The braking strengths of cables produced by a manufacturer have mean 1800 lbs and standard deviation 100lbs. By a new technique in the manufacturing process, it is claimed that the breaking strength can be increased. To test this claim, a sample of 50 cables is tested, and it is found that the mean breaking strength is 1850 lb. 2. The manufacturer of a patent medicine claimed that it was 90% effective in relieving an allergy for a period of 8 hours. In a sample of 200 people who had the allergy, the medicine provided relief for 160 people. 3. An examination was given to two classes consisting of 40 and 50 students, respectively. In the fist class, the mean grade was 74 with a standard deviation of 8, while in the second class, the mean grade was 78 with a standard deviation of 7. Is there a significant difference between the performance of two classes.