Probability
This quiz is designed to test your understanding of probability, a branch of mathematics that deals with the likelihood of events occurring.
Questions
A fair coin is tossed twice. What is the probability of getting two heads?
- 1/2
- 1/4
- 1/8
- 1/16
A bag contains 5 red balls, 3 blue balls, and 2 green balls. What is the probability of randomly selecting a blue ball?
- 5/10
- 3/10
- 2/10
- 1/10
A random variable X has a probability distribution given by P(X = x) = k * x^2, where k is a constant and x = 1, 2, 3. Find the value of k.
- 1/6
- 1/3
- 1/2
- 2/3
Two events A and B are independent. If P(A) = 0.4 and P(B) = 0.6, what is the probability of both A and B occurring?
- 0.24
- 0.16
- 0.12
- 0.08
A box contains 10 defective items and 90 non-defective items. If two items are randomly selected without replacement, what is the probability that both items are defective?
- 1/100
- 1/50
- 1/25
- 1/10
A survey found that 60% of people prefer coffee, 30% prefer tea, and 10% prefer both coffee and tea. What is the probability that a randomly selected person prefers coffee or tea?
- 0.8
- 0.9
- 0.7
- 0.6
A continuous random variable X has a probability density function given by f(x) = 2x for 0 ≤ x ≤ 1. Find the probability that X is less than or equal to 0.5.
- 0.25
- 0.5
- 0.75
- 1
A random variable X follows a normal distribution with mean μ = 10 and standard deviation σ = 2. What is the probability that X is between 6 and 14?
- 0.6827
- 0.9545
- 0.3173
- 0.0455
A company claims that their new product will last for at least 100 hours. A consumer group tests the product and finds that the average lifetime is 95 hours with a standard deviation of 10 hours. Assuming the lifetime follows a normal distribution, what is the probability that a randomly selected product will last for more than 100 hours?
- 0.1587
- 0.8413
- 0.3413
- 0.6587
A bag contains 4 red balls, 3 blue balls, and 2 green balls. If two balls are randomly selected without replacement, what is the probability that the first ball is red and the second ball is blue?
- 3/14
- 6/35
- 2/21
- 1/10
A fair six-sided die is rolled twice. What is the probability of getting a sum of 7?
- 1/6
- 1/12
- 1/18
- 1/24
A survey found that 40% of people prefer coffee, 30% prefer tea, and 20% prefer both coffee and tea. What is the probability that a randomly selected person prefers only coffee?
- 0.2
- 0.3
- 0.4
- 0.5
A random variable X has a probability mass function given by P(X = x) = 1/6 for x = 1, 2, 3, 4, 5, 6. Find the expected value of X.
- 3.5
- 4
- 4.5
- 5
A continuous random variable X has a probability density function given by f(x) = 3x^2 for 0 ≤ x ≤ 1. Find the variance of X.
- 0.25
- 0.5
- 0.75
- 1
A company claims that their new product will last for at least 100 hours. A consumer group tests the product and finds that the average lifetime is 95 hours with a standard deviation of 10 hours. Assuming the lifetime follows a normal distribution, what is the probability that a randomly selected product will last for less than 80 hours?
- 0.0228
- 0.1587
- 0.3413
- 0.8413