The number of species present in samples at both spatial scales differed from randomized expectations; differences between observed and expected species richness values were negatively correlated with total ant abundances, indicating that areas with high ant abundances supported a reduced number of ant species.
When a principal curve is estimated from observed data, this expectation is replaced by a smoothing procedure which estimates the co-ordinates by local averaging.
Because the NRI measures the difference between the observed values and expectation in units of standard deviations, this yields a very simple rule if we assume that possible MPD values are normally distributed: any NRI value larger than 1.96 or smaller than -1.96 is significant.
This observation is consistent with the expectation that observed substitutions in homopolymer runs include artifacts.
Location of the house at the postal code level is shown to explain most of the observed heterogeneity in expectations.
Many past studies have been re-sequenced a gene, and then compared the observed patterns to expectations from computer simulations to assess whether the tested genes stand out (25, 28, 42, 46).
For each genotype model, the goodness of fit (chi-square) and the p-values for the deviation of the number of observed clones from the expectation based on the genotype model are calculated.
Consistent with this expectation, the observed activity for pNPP hydrolysis by R166S AP and Stp1 did not change with ionic strength when the pNPP concentration was well above the expected KM.
To test for regions where marker density significantly deviated from random expectation, the observed numbers of markers per bandwidth were compared to the 95% C.I. of a Poisson distribution with mean and variance equal to n/ LG length/ bw).
When searching for a suitable path P ij that can explain a certain edge i → j, one may restrict the search on paths involving not more edges than a predefined number L. In this way one would manifest the expectation that observed indirect effects can be traced back to short paths.
