An autonomous vehicle test drive results reported failure rate of craches without injuries and measures the impact force. The test of selected car model produces impact forces that are normally distributed with a mean of 30 metric tons and standard deviation of 1.5 metric tons. For a random sample of 3 cars, (i) What is the standard deviation for the sample? (ii) If the car models with crach impact force test higher than 33 metric tons are rejected. Find the percentage of selected car models that will be rejected. (iii) Based on central limit theorem, what will be the shape of sampling distribution of the sample mean impact force? Justify your answer.