John kicks puppies whenever possible and steals the coin jars from homeless people. One could even refer to John as "mean". Every day, the puppies and homeless people come together and rate how mean John was that day on a scale from 1-10. They then take the mean of this data set. The data for the puppies follow a normal distribution with mean of 6 and standard deviation of 2. The ratings from the homeless people also have a normal distribution with mean of 9 and standard deviation of 1. John gets a random sample of 20 puppies and 15 homeless people. Let X1 and X2 be the difference in the sample mean rating (puppies- homeless people). What is the shape of the sampling distribution of X1 - X2? What is the mean and standard deviation of the sampling distribution