The Red Cross anticipates the need for 2000 units of type O blood. If 6% of the population is type O and the Red Cross anticipates 40,000 donations this year,

a) what is the probability they will get at least 2000 units of type 0
b)what is the probability they will get between 3000 and 4000 units?

See this post for the same type of problem:

https://www.askmehelpdesk.com/math-s...al-364152.html

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Originally Posted by galactus

See this post for the same type of problem:

https://www.askmehelpdesk.com/math-s...al-364152.html

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Thanks, I tried the formula but ended up with a standard deviation of about 48, which when calculating z scores gave me numbers above three and less than negative 3. Does that mean that it is 100% chance for part a) z score of -8.89 means the area to the left is zero so the area to the right is 100%. For part b) I get z scores of 35 and 13. The area to the left of them would be 100%, so when subtracted would be 0% chance of this happening.

Am I missing something or calculating something incorrectly
mu = 2400 and sigma = 47.5