2. The patrol police at the Shulin Station on the second highway want to know if the average speed of the truck is too high. Today, 81 trucks were randomly selected to measure their speed, and found that the average speed was 105 kilometers per hour and the standard deviation was 6 kilometers per hour, and it was assumed that the population obeyed the normal distribution. Please answer the following question: Does the average speed of a truck exceed 100 kilometers per hour under a significant level of 0.05? (Please write the null hypothesis and the opposing hypothesis, then calculate the statistic value and P value, respectively, and explain your statistical results). (15 %)