The probability that an individual has 20-20 vision is 0.1. In a class of 10 students, what is the mean andstandard deviation of the number with 20-20 vision in the class?
A) mean: 1; standard deviation: 0.9486833
B) mean: 10; standard deviation: 0.9486833
C) mean: 1; standard deviation: 1
D) mean: 10; standard deviation: 1

Question

Quizplus · Accepted Answer

The mean of a binomial distribution is given by $n \times p$, where $n$ is the number of trials (in this case, 10 students) and $p$ is the probability of success (in this case, 0.1 for having 20-20 vision). Thus, the mean is $10 \times 0.1 = 1$. The standard deviation is given by $\sqrt{n \times p \times (1-p)}$, which calculates to $\sqrt{10 \times 0.1 \times 0.9} = 0.9486833$.

The Probability That an Individual Has 20-20 Vision Is 0