According to a poll, cholesterol levels in healthy adult citizens of a major city average about 240 mg/dL with a standard deviation of 40 mg/dL and are roughly Normally distributed. The cholesterol levels of a sample of 35 healthy adults is taken, Complete parts a through d. a) What is the probability that the mean cholesterol level of the sample will be no more than 240'? (Type an integer or a decimal. Round to three decimal places as needed.)