PValues Data Table

The PValues data table contains a row for each pair consisting of a Y variable and a model Effect. The columns in the table include the following. If you select the Robust Fit option on the launch window, the models are fit using Huber M-estimation.

The specified response columns.

Effect

The specified model effects.

FRatio

The test statistic for a test of the Effect. This is the value found in the Effect Tests report in Least Squares Fit.

PValue

The p-value for the significance test corresponding to the FRatio. See Effect Tests in the Fitting Linear Models book for additional details about Effect Tests.

LogWorth

The quantity -log10(p-value). This transformation adjusts p-values to provide an appropriate scale for graphing. A value that exceeds 2 is significant at the 0.01 level (because -log10(0.01) = 2).

FDR PValue

The False Discovery Rate p-value calculated using the Benjamini-Hochberg technique. This technique adjusts the p-values to control the false discovery rate for multiple tests. For details about the FDR correction, see Benjamini and Hochberg (1995). For details about the false discovery rate, see The False Discovery Rate or Westfall et al. (2011).

FDR LogWorth

The quantity -log10(FDR PValue). This is the best statistic for plotting and assessing significance. Note that small p-values result in high FDR LogWorth values.

Rank Fraction

The rank of the FDR LogWorth expressed as a fraction of the number of tests. If the number of tests is m, the largest FDR LogWorth value has Rank Fraction 1/m, and the smallest has Rank Fraction 1. Equivalently, the Rank Fraction ranks the p-values in increasing order, as a fraction of the number of tests. The Rank Fraction is used in plotting the PValues and FDR PValues in rank order of decreasing significance.

Test DF

The degrees of freedom for the effect test.

The PValues data table also contains a table variable called Original Data that gives the name of the data table that was used for the analysis. If you specified a By variable, JMP creates a PValues table for each level of the By variable, and the Original Data variable gives the By variable and its level.