A leasing firm operates on the belief that the annual mean number of miles driven in its leased cars is 18,500. To see whether this belief is valid, a random sample of 15 one-year-old cars were checked and the sample mean was 19,100 and standard deviation 3,750 miles. Which assumptions or conditions are not met for this hypothesis testing problem. If all are okay then choose "None." Randomization Assumption Independence Assumption en big enough?