1. A plastic surgeon wants to compare the number of successful skin grafts in her series of burn patients with the number in other burn patients. A literature survey indicates that approximately 30% of the grafts become infected but that 80% survive. She has had 7 of 8 skin grafts survive in her series of patients and has had one infection.

a. How likely is it that there is only 1 out of 8 infections?

b. How likely is survival in 7 of 8 grafts?

c. How likely is it that there are less than 4 infections?

d. How likely is it that there are at least 3 infections?

e. How likely is it that there are between (inclusive) 3 and 5 survivals?

f. How many infections would you expect to have in the 8 skin grafts?

g. What is the standard deviation for the number of infections in the 8 skin grafts?

2. The values of serum sodium in healthy adults approximately follow a normal distribution with a mean of 141 mEq/L and a standard deviation of 3mEq/L.

a. What is probability that a normal healthy adult will have a serum sodium value above 147 mEq/L?

b. What is the probability that a normal healthy adult will have a serum sodium value below 130 mEq/L?

c. What is the probability that a normal healthy adult will have a serum sodium value between 132 and 150 m/EqL?

d. What is the probability that a sample of 4 normal healthy adults will have a serum sodium value below 140?

e. What serum sodium level is necessary to put someone in the top 1% of the distribution?

f. What serum sodium level is necessary to put someone in the bottom 10% of the distribution?