Hello, I'm having trouble figuring out how to calculate a p-value for a 1-tailed test of beta_1 in a linear model fit using command lm. My model has only 1 continuous, predictor variable. I want to test the null hypothesis beta_1 is >= 0. I can calculate the p-value for a 2-tailed test using the code "2*pt(-abs(t-value), df=degrees.freedom)", where t-value and degrees.freedom are values provided in the summary of the lm. The resulting p-value is the same as provided by the summary of the lm for beta_1. I'm unsure how to change my calculation of the p-value for a 1-tailed test.
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