# What does it mean if my confidence interval includes zero with a significant p value in linear regression analysis?

I performed linear regression analysis to assess the associations between continuous variables. I found a significant p-value but my confidence interval includes zero. What does it mean? Here are the results;

β= -0.267

SE: 0.000

95 CI= -0.002 to 0.000

p=0.000

• This output seems to be unrelated to the question, because there is no interval shown that includes zero. The two intervals are $[0.7, 2.1]$ and $[-0.0017, -0.0004]$.
– whuber
May 13 at 12:20

Thank you for the screenshot. The unstandardized coefficient is $$-0.00108$$ (rounded to three significant digits) with a corresponding 95% confidence interval of $$(-0.00172; -0.000445)$$ and a $$p$$-value of $$0.000996$$. The $$p$$-value is below $$0.05$$ and correspondingly, the 95% confidence interval does not include $$0$$. There is no contradiction.
The standardized coefficient is $$-0.267$$ but a confidence interval is not provided for this coefficient. The $$p$$-value does not change, however. If you're interested in calculating a confidence interval for the standardized coefficient, I have summarized the steps in my answer to another post.
As @NickCox rightly states: The predictor is probably on a large scale which leads to very small coefficients and confidence limits because the coefficients are for an increase in 1 unit. To get the change per $$x$$ units, divide the predictor by $$x$$ before calculating the regression. For example: If the predictor is money in US dollars, divide by 1000 to calculate the change for an increase in \\$1000.