The reduction in cholesterol level after eating a certain brand of oatmeal for breakfast for one month in people with cholesterol levels over 200 is Normally distributed, with mean (in milligrams) and standard deviation = 9. Although the brand advertises that eating their oatmeal for breakfast daily for one month will produce a mean decrease in cholesterol of more than 20 points for people with cholesterol levels over 200, you believe that the mean decrease in cholesterol is actually less than advertised. To explore this, you test the hypotheses

H₀: =20, H_a: < 20 at the 0.05 significance level.

You will do this by randomly selecting 140 people with cholesterol levels over 200 and, after eating this brand of oatmeal for one month, computing the mean decreasexx in cholesterol levels of the subjects. If you observe a sample mean cholesterol reduction ofxx = 18.47, the P-value obtained is?