Suppose the heights of 18-year-old men are approximatelynormally distributed, with mean73inches and standard deviation4inches.

(a) What is the probability that an 18-year-old man selected at random is between72and74inches tall? (Round your answer to four decimal places.)

(b) If a random sample offourteen18-year-old men is selected, what is the probability that the mean heightxis between72and74inches? (Round your answer to four decimal places.)

Letxbe a random variable that represents the level of glucose in the blood (milligrams per deciliter of blood) after a 12 hour fast. Assume that for people under 50 years old,xhas a distribution that is approximately normal, with mean=76and estimated standard deviation=42. A test resultx<40 is an indication of severe excess insulin, and medication is usually prescribed.

(a) What is the probability that, on a single test,x<40? (Round your answer to four decimal places.)

What is the probability thatx<40? (Round your answer to four decimal places.)

(c) Repeat part (b) forn= 3 tests taken a week apart. (Round your answer to four decimal places.)

(d) Repeat part (b) forn= 5 tests taken a week apart. (Round your answer to four decimal places.)

Letxbe a random variable that represents white blood cell count per cubic milliliter of whole blood. Assume thatxhas a distribution that is approximately normal, with mean=7200and estimated standard deviation=2500.A test result ofx<3500is an indication of leukopenia. This indicates bone marrow depression that may be the result of a viral infection.

(a) What is the probability that, on a single test,xis less than 3500? (Round your answer to four decimal places.)

What is the probability ofx<3500? (Round your answer to four decimal places.)

(c) Repeat part (b) forn= 3 tests taken a week apart. (Round your answer to four decimal places.)

A European growth mutual fund specializes in stocks from the British Isles, continental Europe, and Scandinavia. The fund has over325stocks. Letxbe a random variable that represents the monthly percentage return for this fund. Supposexhas mean=1.6%and standard deviation=1.1%.

(b) After 9 months, what is the probability that theaveragemonthly percentage returnxwill be between 1% and 2%? (Round your answer to four decimal places.)

(c) After 18 months, what is the probability that theaveragemonthly percentage returnxwill be between 1% and 2%? (Round your answer to four decimal places.)

(e) If after 18 months the average monthly percentage returnxis more than 2%, would that tend to shake your confidence in the statement that=1.6%?If this happened, do you think the European stock market might be heating up? (Round your answer to four decimal places.)

P(x> 2%) =

The taxi and takeoff time for commercial jets is a random variablexwith a mean of8.7minutes and a standard deviation of3.5minutes. Assume that the distribution of taxi and takeoff times is approximately normal. You may assume that the jets are lined up on a runway so that one taxies and takes off immediately after the other, and that they take off one at a time on a given runway.

(a) What is the probability that for35jets on a given runway, total taxi and takeoff time will be less than 320 minutes? (Round your answer to four decimal places.)

(b) What is the probability that for35jets on a given runway, total taxi and takeoff time will be more than 275 minutes? (Round your answer to four decimal places.)

(c) What is the probability that for35jets on a given runway, total taxi and takeoff time will be between 275 and 320 minutes? (Round your answer to four decimal places.)