Prism tests the statistical significance of each parameter.
The null hypothesis is that the true population value of the parameter is 0.0. What this means is that the corresponding variable simply has no impact on the outcome variable. The P value answers the question:
If that null hypothesis were true, what is the chance that analysis of a randomly selected data sample will result in a parameter as far, or further, from zero than reported from this analysis?
For each parameter, Prism reports:
•The absolute value of t, which is computed as the parameter value divided by its standard error. With Poisson regression, Prism reports the absolute value of z instead.
•The P value which is computed from the t ratio and the number of degrees of freedom (equal to the number of rows of data minus the number of columns of data).
•A P value summary, as ns or one or more asterisks.