Chapter 7 Data Screening From: McCune, B. & J. B. Grace Analysis of Ecological Communities. MjM Software Design, Gleneden Beach, Oregon Tables, Figures, and Equations

Figure 7.1. Frequency distribution showing a univariate outlier falling 5.5 standard deviations above the mean.

Table 7.1. Steps to detect, describe, and reduce the influence of outliers.

Figure 7.2. A bivariate outlier that is not a univariate outlier for either of the two variables Sp1 and Sp2.

Table 7.2. Deviations of the mean distance to an outlying sample unit from the average distance among sample units, using five distance measures. ( based on artificial noiseless data set of smooth species responses, with one SU disrupted by anomalous values.)

Figure 7.3. Frequency distribution of average relative Euclidean distances to particular sample units with a total of 25 sample units. The sample unit represented by the rightmost bar is 3.2 standard deviations above the mean of the average distances.