Your friend Sergei claims that the average number of Skittles in a bag is 50. You believe the true mean is different. Therefore, you decide to test the null hypothesis that the true mean is equal to 50 versus the alternative that the true mean is not equal to 50. In order to test this, you collect 15 bags of Skittles and count the number of Skittles in each bag. You compute x=51, s=2

answer: 0.073

please explain in detail