I have two data sets, both are normally distributed (p<0.05). When I run a two sample t-test to assess if there is a significant difference between the means, I get a p-value of exactly zero?
What does this mean? I have never encountered it before. Below is the output from Minitab for the test.
Thank you all for your time.
Regards,
Tom
Two-sample T for 50_0.22 vs 50_0.12
N Mean StDev SE Mean
50_0.22 4709 1.48 1.48 0.022
50_0.12 4709 1.23 1.00 0.015
Difference = μ (50_0.22) - μ (50_0.12)
Estimate for difference: 0.2477
95% CI for difference: (0.1967, 0.2986)
T-Test of difference = 0 (vs ≠): T-Value = 9.53 P-Value = 0.000 DF = 8286
Best Answer
The p-value is not really 0, it's just being reported as 0 in that output because it's being rounded down and it looks like the output can only display 3 digits after the decimal.