Lemma
MediumContinuous distributions
OpenStax, Introductory Business Statistics 2e §5.3 The Exponential Distribution · Exercise 38 · Probability · Continuous distributions

The Exponential Distribution · Exercise 38

According to the American Red Cross, about one out of nine people in the U.S. have Type B positive blood. Suppose the blood types of people arriving at a blood drive are independent. In this case, the number of Type B positive blood types that arrive roughly follows the Poisson distribution.

(a) If 100 people arrive, how many on average would be expected to have Type B positive blood?
(b) What is the probability that over 10 people out of these 100 have type B positive blood?
(c) What is the probability that more than 20 people arrive before a person with type B positive blood is found?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

~8 minWritten answer · check your work with Lemma

OpenStax, Introductory Business Statistics 2e · §5.3 The Exponential Distribution · Exercise 38

Stuck? A gentle nudge

No hints for this one.

Something off?
Workspace
Your working

Check your full solution

Attach photos of your pages (up to 3) or one PDF — or check what you typed above. Lemma reads the work and verifies the reasoning, not just the answer.

Your first check today doesn't need an account.

Your photos and PDFs are read once and not stored — only the transcription is kept.