# Which P value do I use?

I have two different p-values here, do I use the Pr( t ) or the regular p-value?

Call:
lm(formula = ddd ~ CON, data = data)

Residuals:
Min      1Q  Median      3Q     Max
-0.5726 -0.4859 -0.4570  0.5141  0.5430

Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept)  1.60144    0.09117  17.565   <2e-16 ***
CON         -0.02889    0.02360  -1.224    0.222
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 0.5004 on 315 degrees of freedom
Multiple R-squared:  0.004735,  Adjusted R-squared:  0.001575
F-statistic: 1.499 on 1 and 315 DF,  p-value: 0.2218

• What model are you using? There are p-values associated with regression parameters and for the overall fit F test. So it depends on which one you are talking about. – Michael Chernick May 1 '17 at 20:46

## 1 Answer

Because you fit a simple regression model (one covariate), so the p-value for slop (0.222) and overall F-test p-value (0.2218) are the same thing. If you ask the program give you one more digit on slop p-value, you will get 0.2218, instead of 0.222.

About p-value for intercept (<2e-16), I think you are not interested in it.