Melody

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Melody  Feb 11, 2022
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I've been mucking around with this for ages and I finally worked out how to do in in Wolfram Alpha.

 

https://www.wolframalpha.com/input/?i=sum+(5!%2F(n!*(5-n)!)*0.3%5En*0.7%5E(5-n)),++n%3D0+to+2

 

I am sure there is a probability calc that will work it out a lot easier though.....

 

Here is the first one that I found but I am sure that there are plent of others about.

http://www.vassarstats.net/textbook/ch5apx.html

See, it is the probability of 2 or fewer than 2 that you want.   

The two calculators give the same answer   laugh

 

Nov 1, 2016