Probability; help pls! Exercise 1: Let X be a random variable which, to each man sampled at random, associates his height in centimeters. We assume that X follows the normal distribution with mean 178 and standard deviation 10. Determine the probability of each of the following events: A: “A man taken at random has a height strictly greater than 180”. B: “A man taken at random has a height less than or equal to 150”. C: “A randomly selected man has a height between 160 and 185.”
Exercise 1:
Let X be a random variable which, to each man sampled at random, associates his height in centimeters.
We assume that X follows the
- Determine the probability of each of the following
events:
A: “A man taken at random has a height strictly greater than 180”.
B: “A man taken at random has a height less than or equal to 150”.
C: “A randomly selected man has a height between 160 and 185.”
- Determine the real a such that P(X ≥ a) = 0, 2
- Determine the real b such that P(176 − b ≤ X ≤ 180 + b) = 0.68
Exercise 2:
Let X be a random density variable
f(x) = { e−2θx if x ≥ 0
0 else
- Find θ so that f is a probability density.
- Determine the distribution
function F of the variable X. - Calculate the expectation and variance of X.
- Let Y be the random variable defined by Y = θX. What is the law of Y?
Exercise 3:
In a garden center: 25% of the plants are less than a year old, 60% are 1 to 2 years old, 25% have yellow flowers, 60% have pink flowers, 15% have yellow flowers and less than a year old , 3% are more than 2 years old and have neither yellow nor pink flowers. 15% of those who are 1 to 2 years old have
yellow flowers, 15% of those 1-2 years old have neither yellow nor pink flowers. It is assumed that the flowers cannot be both yellow and pink at the same time. We choose a plant at random in this garden center.
- What is the probability that it is less than a year old and has pink flowers?
- What is the probability that she has pink flowers, given that she is over 2 years old?
- What is the probability that it is over two years old and has yellow flowers?
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Probability; help pls!
Exercise 1:
Let X be a random variable which, to each man sampled at random, associates his height in centimeters.
We assume that X follows the
- Determine the probability of each of the following
events:
A: “A man taken at random has a height strictly greater than 180”.
B: “A man taken at random has a height less than or equal to 150”.
C: “A randomly selected man has a height between 160 and 185.”
- Determine the real a such that P(X ≥ a) = 0, 2
- Determine the real b such that P(176 − b ≤ X ≤ 180 + b) = 0.68