The mean age of participants in your study is 20.1 years with a standard deviation of 2.7 years. As you write up your results, you realize that what matters is the ages of the participants two years ago when the event happened, not their ages now. You decide to subtract 2 from each of your participants’ ages. After you subtract 2 years, the mean age in your sample is18.1 years. The new standard deviation of the ages in your sample is years.