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The bacterium Mathorio Statalis have diameters that are normally distributed with mean 9 nm and standard deivation 3.8 nm.

• A researcher does not know these parameters and measures a Mathorio Statalis to have a diameter of 11 nm. What is the probability a randomly-chosen bacterium of this species has a diameter of under 11 nm?
• To learn what the parameters are for this disease, the researcher measures the diameter of 25 bacteria. What is the probability that a sample of 25 bacteria will have a mean average diameter under 11 nm?