CA Foundation · Quantitative Aptitude · Theoretical Distributions
For a Poisson distribution, which of the following statements is correct?
In a Poisson distribution the mean and the variance are equal, and both are given by the parameter m. This is its defining feature, and it distinguishes it from the binomial distribution, where the variance is smaller than the mean.
- AMean is greater than variance
- BMean equals varianceCorrect
- CVariance is the square of the mean
- DMean is the square root of the variance plus one
Explanation
In a Poisson distribution with parameter m, both the mean and the variance equal m. Hence the mean is not greater than the variance, and variance is the square of the mean only when m is 1 or 0.
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