The PROC REG output contains two-sided tests. If you were to do a two-sided test at the alpha=0.05 level, then 0.025 chance of a type I error is in the upper tail and 0.025 chance of a type I error is in the lower tail.
You want a one-sided test with alpha=0.05 in one tail and alpha=0 in the other tail. So, if the pvalue from SAS is <0.10, your one-sided test is statistically significant at the alpha=0.05 level, because 0.05 chance of type I error in one tail, and 0 percent chance of type I error in the other tail.
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