10. a) The scores on an exam had a mean of 80 and a standard deviation of 15. If the grades are curved by adding 5 points to each, the revised data have mean standard deviation b) You are about to purchase a new car battery. Brand A has a mean life of 48 months with standard deviation 4 months. Brand B has A mean life of 52 months with a standard deviation of 10 months. which should you buy? Why? c) which is better, a score of 60 on a test with mean 50 and standard deviation 5, or a score of 75 on a test with mean 70 and standard deviation 10. Why? d) The printed program for a symphony concert included a phone number to call to respond to the question of increased government funding of the arts. Ten responses were received, and the orchestra's support organization proudly proclaimed that 95% of the population approved of this increase. What is wrong with this survey?