Mean, Mode, Median, and Standard Deviation The  Mean and Mode The  sample mean  is the  average  and is computed as the sum of all the observed outcomes  from the sample divided by the total number of events.  We use  x  as the symbol for the sample mean.  In math terms,             where  n  is the  sample size  and the  x  correspond to the  observed valued . Example Suppose you randomly sampled six acres in the Desolation Wilderness for a non-indigenous weed and came up with the following counts of this weed in this region:          34, 43, 81, 106, 106  and  115  We compute the sample mean by adding and dividing by the number of samples, 6.              34 + 43 + 81 + 106 + 106 + 115          ...