An environmental scientist obtains a sample of water from an irrigation canal that contains a certain type of bacteria at a concentration of 4 per milliliter. Find the standard
Deviation of the number of bacteria in a 6-milliliter sample.
A) 24
B) 2
C) 4.9
D) 4

Question

Quizplus · Accepted Answer

The standard deviation in this context is found using the formula for the standard deviation of a Poisson distribution, which is the square root of the mean. Given the concentration is 4 bacteria per milliliter, for a 6-milliliter sample, the mean ($\lambda$) is $4 \times 6 = 24$. The standard deviation is the square root of this mean, $\sqrt{24} \approx 4.9$.

An Environmental Scientist Obtains a Sample of Water from an Irrigation