Discrete Binomial chart questions

akakelsy

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Using the chart that I've uploaded, the question begins:
75% of teenagers and adults in the US were deficient in Vit. D. If a total of 10 American teenagers and adults were chosen at random, use the chart to figure:


1.)The probability that exactly 4 were deficient in Vit. D = I got 0.016 looking under the 0.75 column


2.) The probability that more than 8 were deficient in Vit.D = I got 0.244 if I added the 9 and 10 values on the 0.75 column


3.) The probability that 6 or more were not deficient in Vit.D= I thought to add up the values for 6 or more which was 0.922 and subtracted by 1 because the question stated "were not" and got 0.0078


Is my thinking correct?


Best,
 

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attachment.php


Using the chart that I've uploaded, the question begins:
75% of teenagers and adults in the US were deficient in Vit. D. If a total of 10 American teenagers and adults were chosen at random, use the chart to figure:


1.)The probability that exactly 4 were deficient in Vit. D = I got 0.016 looking under the 0.75 column


2.) The probability that more than 8 were deficient in Vit.D = I got 0.244 if I added the 9 and 10 values on the 0.75 column


3.) The probability that 6 or more were not deficient in Vit.D= I thought to add up the values for 6 or more which was 0.922 and subtracted by 1 because the question stated "were not" and got 0.0078


Is my thinking correct?


Best,
Q1 and Q2 look fine
Q3 "6 or more not deficient" means 6, 7, 8, 9 or 10 not deficient. In other words 4, 3, 2, 1, or 0 are deficient.
So you need to add the probs from 0 to 4 to get 0.019

Bit hard to get your head around but
"6, 7, 8, 9 or 10 are not deficient" is NOT the same as "not 6, 7, 8, 9 or 10 are deficient".
 
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