Answer:
The standard deviation of the number of haunted houses in a large city is 3.
Step-by-step explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:
[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]
In which
x is the number of sucesses
e = 2.71828 is the Euler number
[tex]\mu[/tex] is the mean in the given interval, which is the same as the variance.
According to ghost hunters, large cities have, on average, 9 haunted houses each.
This means that [tex]\mu = 9[/tex]
a) What is the standard deviation of the number of haunted houses in a large city?
Square root of the variance, so:
[tex]\sqrt{9} = 3[/tex]
The standard deviation of the number of haunted houses in a large city is 3.