Final answer:
To calculate the probability that x=0 for a Poisson distribution with mean μ=0.4, we use the probability mass function and find it to be approximately 0.6703. To find the probability that x>0, we subtract this value from 1 to get 0.3297. The distribution has a mean of 0.4, with variance also being 0.4 and the standard deviation approximately 0.63.
Step-by-step explanation:
The Poisson distribution is used to model the probability of a number of events occurring within a fixed interval of time or space. For a Poisson distribution with a mean (μ) of 0.4:
- To find the probability that x=0, which is P(X=0), we use the Poisson probability mass function: P(X=x) = (μx * e−μ) / x!. Substituting in the values for x=0 and μ=0.4, we get P(X=0) = (0.40 * e−.4) / 0! = 0.6703 after rounding to four decimal places.
- To find the probability that x>0, we subtract the probability that x=0 from 1: P(X>0) = 1 - P(X=0). Using the previously calculated P(X=0), we get P(X>0) = 1 - 0.6703 = 0.3297 after rounding to four decimal places.
- The mean of the Poisson distribution is given by μ, which in this case is 0.40.
- The variance of the Poisson distribution is also μ, so the variance is also 0.40.
- The standard deviation is the square root of the variance, giving us a standard deviation of √0.40, which is approximately 0.63 when rounded to two decimal places.