File Edit Go CONTENTS Tools Help Section 4 An Extended Exploration The t Test Isle Royale is meaningful if the probability of it occurring by chance alone its p value is less than 0 05 How do you obtain a p value Given the value of t and something called the degrees of freedom in your data you can determine the p value using a handy dandy t test p value calculator The number of degrees of freedom in your t test is equal to the total number of samples 12 in this case minus 2