What is the expected value of a continuous random variable? What is the expected value of an exponentially distributed random variable?

True or False? Assume a doctor uses a specific form of mesh to repair all hernias in his hernia patients. The makers of the mesh found there was an error that occurred while making the mesh, and the hernia mesh has a 45% chance of failure. The doctor has treated 7 patients with the mesh so far; thus, the probability that the mesh does not fail in all seven patients is .0152.

Determine the probability (as a decimal rounded to the nearest ten-thousandth) of a standard normal random variable realizing a value that is between one half and two.

Let X be a random variable with range {20,30,50} and probability distribution P(X=20) = 0.25,P(X=30) = 0.25, and P(X=50) = 0.5. What is the expected value of X?