You want to calculate the mean and variance of the sample data collected last week. Your study measured the number of trees/10m 2 on the trail...

You want to calculate the mean and variance of the sample data collected last week.  Your study measured the number of trees/10m2 on the trail (TRAIL) and off the trail (WOODS).  You did this at 3 different locations (A, B, C). TRAIL data for location A was 12 trees,  B  was 3, and C was 9. What is the variance of your data?