6. Oatmeal is a food that is high in fiber and low in fat. A dietician says, "People who regularly eat oatmeal tend to have lower cholesterol." A group of 121 randomly selected adult women who regularly eat oatmeal has a sample mean total cholesterol of 185 mg/dL.

a. What is the probability a randomly selected group of adult women has a sample mean total cholesterol of 185 or less?

Give a decimal, not a percent. Round your answer to four decimal places.