Probability distributions - binomial, Poisson, normal, gamma, beta, Cauchy, multinomial, hypergeometric, negative binomial - One Line Questions

1. The median of a standard Normal distribution (mu=0, sigma=1) is: 0
2. In a binomial experiment, if n=10 and p=0.5, what is the probability of getting exactly 5 successes? 0.246
3. In the context of the Beta distribution, if alpha = 1 and beta = 1, what distribution does it represent? A uniform distribution on [0, 1]
4. The Gamma distribution is a generalization of the exponential distribution. If the shape parameter k=1, the Gamma distribution becomes: An Exponential distribution
5. The Multinomial distribution is a generalization of the binomial distribution. It describes the outcome of: A fixed number of independent trials, each with more than two possible outcomes
6. A single draw from a Multinomial distribution with parameters n and p1, p2, ..., pk results in: A vector of k counts, summing to n, representing the number of times each outcome occurred.
7. Consider a sequence of Bernoulli trials. The Negative Binomial distribution models the probability of obtaining: A specific number of failures before the k-th success.
8. Which distribution is characterized by the probability of k successes in n trials, where sampling is done WITHOUT replacement from a finite population of size N containing K successes? Hypergeometric
9. When sampling from a finite population without replacement, if we are interested in the number of successes in a fixed number of draws, which distribution is appropriate? Hypergeometric distribution
10. If a die is rolled 10 times, and we are interested in the number of times each face (1 through 6) appears, which distribution would model this scenario? Multinomial distribution
11. A box contains 10 red balls and 5 blue balls. If 3 balls are drawn without replacement, the probability distribution for the number of red balls drawn follows: Hypergeometric distribution
12. The Beta distribution is related to the Gamma distribution through the Beta function B(x, y) = Gamma(x)Gamma(y) / Gamma(x+y). This relationship is useful for: Both A and B.
13. The Cauchy distribution's heavy tails mean that: Extreme values are more likely than in a normal distribution.
14. Which continuous probability distribution is bell-shaped, symmetric, and characterized by its mean (mu) and standard deviation (sigma)? Normal distribution
15. Which distribution is characterized by the probability density function f(x) = (1 / (sigma * sqrt(2*pi))) * exp(-0.5 * ((x - mu) / sigma)^2)? Normal distribution
16. The Cauchy distribution has a characteristic function (phi(t)) given by exp(|t|). This implies: It has heavy tails.
17. Which of the following is a property of the Normal distribution? It is symmetric about its mean.
18. The variance of a Poisson distribution with parameter lambda is: lambda
19. The Cauchy distribution is known for its heavy tails and lack of a well-defined mean or variance. What is its characteristic parameter? Mu (location) and Sigma (scale)
20. The probability density function of a Poisson distribution with parameter lambda is given by P(X=k) = (lambda^k * e^(-lambda)) / k! for k = 0, 1, 2, ... . This formula is valid when: lambda > 0.
21. If X follows a Poisson distribution with parameter lambda, what is the expected value (mean) of X? lambda
22. What are the parameters of a Beta distribution, typically denoted by alpha and beta? Two positive shape parameters
23. In a standard normal distribution, what are the values of the mean and standard deviation? Mean = 0, Standard Deviation = 1
24. What are the parameters of a Gamma distribution, typically denoted by k (shape) and theta (scale)? Shape and Scale
25. The probability density function of the Cauchy distribution is f(x; x0, gamma) = 1 / (pi * gamma * [1 + ((x - x0)/gamma)^2]). Here, x0 and gamma represent: Location and Scale
26. The Poisson distribution is often used to model the number of events occurring in a fixed interval of time or space, provided these events occur with a known average rate and independently of the time since the last event. What parameter characterizes the Poisson distribution? lambda (average rate of occurrence)
27. Which parameters define a Hypergeometric distribution? N (population size), K (number of success states in population), and n (number of draws)
28. The Gamma function, denoted by Gamma(z), is fundamental to the Gamma distribution. What is Gamma(n) for a positive integer n? (n-1)!
29. When the number of trials 'n' in a binomial distribution becomes very large and the probability of success 'p' becomes very small, such that np = lambda (a constant), the binomial distribution can be approximated by which other distribution? Poisson distribution
30. Which distribution is characterized by the fact that the sum of two independent Gamma random variables with parameters (k1, theta) and (k2, theta) is a Gamma random variable with parameter (k1+k2, theta)? Gamma distribution
31. The sum of 'n' independent and identically distributed standard normal random variables follows a: Chi-squared distribution with n degrees of freedom
32. For a binomial distribution B(n, p), what is the variance? np(1-p)
33. The Normal distribution can be used to approximate the Binomial distribution when 'n' is large and 'p' is not too close to 0 or 1. What condition is typically used to determine if the approximation is valid? np > 5 and n(1-p) > 5
34. Which probability distribution is characterized by a fixed number of independent trials, each with two possible outcomes (success or failure), and a constant probability of success? Binomial distribution
35. The limiting distribution of the sum of a large number of independent and identically distributed random variables (under certain conditions) is the: Normal distribution
36. What is a common parameterization for the Negative Binomial distribution, often denoted by r and p? r = number of successes, p = probability of success
37. Which of the following statements about the Normal distribution is FALSE? The total area under the curve is infinite.
38. The Cauchy distribution is sometimes called the 'Lorentz distribution'. A key characteristic is that its mean is undefined because: The integral of x*f(x) from -infinity to +infinity does not converge.
39. In a multinomial distribution with k possible outcomes, what do the parameters typically represent? The number of trials and the probability of each outcome
40. The Negative Binomial distribution parameter 'r' typically represents: The target number of successes.
41. The Gamma distribution is a continuous probability distribution often used to model: The waiting time until a certain number of events occur
42. The Negative Binomial distribution describes the probability of: The number of failures before the r-th success
43. The Negative Binomial distribution can be viewed as the distribution of the number of trials needed to achieve a fixed number of successes. What is the alternative definition? The number of failures before the r-th success.
44. A common application of the Beta distribution is in Bayesian statistics for modeling: The posterior distribution of a probability parameter.
45. In a binomial distribution B(n, p), what does 'n' represent? The total number of independent trials
46. The sum of independent Gamma random variables with the same scale parameter is also a Gamma random variable. What is the shape parameter of the resulting distribution? The sum of the original shape parameters.
47. The Beta distribution is often used to model probabilities or proportions, which are bounded between 0 and 1. If alpha > 1 and beta > 1, the Beta distribution will be: Unimodal and concentrated around the mean
48. The Beta distribution is a continuous probability distribution defined on the interval [0, 1]. It is often used to model: Proportions or percentages
49. The variance of a Binomial distribution B(n, p) is always less than or equal to its mean (np). When is the variance equal to the mean? When p = 0
50. The Hypergeometric distribution is used when sampling is done: Without replacement