A wide variety of oak trees grow in the United States. In one study, a sample of acorns was collected from different locations, and their volumes, in cm3, were recorded. In the table are summary statistics for these data:

Question

N 38
Mean 3.0
Median 1.8
St. Dev. 2.6
Minimum 0.3
Maximum 10.5
1st Quartile 1.1
3rd Quartile 4.3
Describe a procedure that uses some or all of these summary statistics to determine whether outliers are present in the data.

Answer 1

Since the mean is larger than the median, the distribution is positively skewed. The mean ± 2 standard deviations covers about 95% of scores in a normal distribution. That should start you going.