1. After surgery to replace an arthritic hip joint, the short-term recovery times until the patient is able to walk without assistance or pain are normally distributed, with a mean of 34 days and a standard deviation of 5.6 days. If a patient receiving a new hip joint is randomly selected, determine the probability that (s)he will have a short-term recovery time of less than 21 days i.e. P(X<21) (use formula:)

a. 0.1456

b. 0.0102

c. 0.0067

d. 0.1942 2. In the following example, calculated the Expected value

P( 0 < X < 0.86 ), given that X is selected randomly from the interval is 0 to 5

(Use formula: Expected value = )

a. 0.12

b. 2.5

c. 1.3

d. 0.27 3. The lifespan of an X-ray tube used as part of an X-ray imaging machine follows a normal distribution with a mean of 3.38 years and a standard deviation of 0.466 years. Calculate the probability that a randomly-selected X-ray tube will have a lifespan of less than 3.26 years i.e. P(X < 3.26)

(use formula: )

a. 0.3974

b. 0.4120

c. 0.0156

d. 0.1172

4. If Z is a continuous random variable with a standard normal distribution, determine the following probability using standard normal distribution table:

P ( Z < -1.53 )

a. 0.063

b. 0.451

c. 0.162

d. 2.913