P for trend = .004
Can someone tell me what this means? The whole sentence is:
"an increased risk of squamous cell carcinomas in the entire respiratory tract (P for trend = .004)"
There is also a sentence which is difficult:
The relative risk of squamous cell carcinomas among long-term incense users was 1.8 (95% confidence interval [95% CI], 1.2-2.6; P = .004) in the entire respiratory tract.