1. the national highway traffic safety administration indicated that 284 people died between 1990 and 2007 as a result of an injury caused by an airbag. newer airbags open at a speed proportional to the speed of an impact. older models open at a constant speed, up to 200 mph, equal to the force of a heavyweight knockout punch. a random sample of 40 older-model airbags was obtained and tested. the average opening speed for each older-model airbag was 173.88. airbag opening speed is normally distributed with =10 mph. compute a 90% confidence interval for the mean opening speed in older-model airbags. be sure to check all necessary assumptions and conditions, and interpret your interval within the context of the problem.