Mean and Variance of a Binomial Distribution
Suppose that 60% of American adults approve of the way the president is handling his job, and we randomly sample two American adults. Let the random variable X represent the number of those adults that approve. X can take on the values 0, 1, or 2. Calculate the mean and the variance of this probability distribution.
This problem falls within the realm of discrete probability, specifically focusing on binomial distributions. In a binomial distribution, there are a fixed number of trials, each with two possible outcomes. In this case, the outcomes are whether an adult approves of the president's handling of the job or not. The basis of solving this problem lies in understanding the properties of binomial distributions, particularly how to calculate its mean and variance.
The random variable X, which represents the number of approvals in this sample, is a quintessential example of a binomial random variable. The binomial distribution has two fundamental parameters: the number of trials (n) and the probability of success in each trial (p). Here, n is 2, and p is 0.6. For a binomial distribution, the mean can be calculated by multiplying the number of trials (n) by the probability of success (p). The variance is derived from the formula n times the probability of success times the probability of failure, which is (1-p).
Understanding these foundational characteristics of the binomial distribution is crucial, as they apply to a wide variety of problems in probability. Mastery of calculations like these offers insight into the behavior of probabilistic systems and the principles governing random phenomena, making them invaluable for further studies in both mathematics and applied sciences.
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