NoahRogers4932
New member
- Joined
- Nov 24, 2014
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1. The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 266 days and standard deviation 16 days. Choose two pregnancies independently and at random.
a) What is the expected difference in the lengths of the two pregnancies?
b) What is the standard deviation of the difference in the lengths of the two pregnancies?
c) Find the probability that the difference in the lengths of the two pregnancies is greater than 25 days.
2. Witney Pete, a professional dart player, has a 70% chance of hitting the bull’s eye on a dartboard with any throw. Assume that each throw of a dart is independent.
a) Suppose Pete throws darts until he hits his first bull’s eye. Find the probability that his first bull’s eye occurs on the third throw.
b) What is the probability that Pete hits 5 or fewer of his next 10 shots?
c) Pete forgets his eyeglasses one evening, but he’s confident he’s just as accurate without them. On his first 10 shots of the night, he hits the bull’s eye only 5 times. Is this evidence that his glasses are important? Explain.
For 1c I was able to get that the answer i going to be P( 240 < z < 282) but I don't know where to go from there.
For number 2 I have no clue
This is due tomorrow so urgent help would be greatly appreciated
a) What is the expected difference in the lengths of the two pregnancies?
b) What is the standard deviation of the difference in the lengths of the two pregnancies?
c) Find the probability that the difference in the lengths of the two pregnancies is greater than 25 days.
2. Witney Pete, a professional dart player, has a 70% chance of hitting the bull’s eye on a dartboard with any throw. Assume that each throw of a dart is independent.
a) Suppose Pete throws darts until he hits his first bull’s eye. Find the probability that his first bull’s eye occurs on the third throw.
b) What is the probability that Pete hits 5 or fewer of his next 10 shots?
c) Pete forgets his eyeglasses one evening, but he’s confident he’s just as accurate without them. On his first 10 shots of the night, he hits the bull’s eye only 5 times. Is this evidence that his glasses are important? Explain.
For 1c I was able to get that the answer i going to be P( 240 < z < 282) but I don't know where to go from there.
For number 2 I have no clue
This is due tomorrow so urgent help would be greatly appreciated