Kenneth S. answered • 10/17/17
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Expert Help in Algebra/Trig/(Pre)calculus to Guarantee Success in 2018
this term represents 0 purchases: 0.810
this term represents 1 purchase: 10(0.2)(0.89) ... note binary coefficient 10C1
this term is for 2 purchases: 45(0.22)(0.88) ... note binary coefficient 10C2
for 3 purchases: 120(0.23)(0.87) ... note binary coefficient 10C3
This totals 0.879126 and it's probability of 3 or less sales.
P(4 or more sales) = 1- the above = 0.12087
I believe that your answer might be right but had early rounding whereas mine did not. Very close!
Kenneth S.
It appears from what you say that you are being TRAINED to write function calls, whereas I approached the problem based on understanding of the binomial probability distribution. It's based on expansion of (F+S)10 and there will be eleven terms, each of which has a coefficient (from Pascal's triangle) that expresses how many ways there are to have exactly r Sucesses, in ten trials, where probability of success is S and probability of failure is F, and S+F = 1. The exponents on S & F in each term total 10; the term.
Now, back to your training. Consult the manual, and notes, etc. to get precise definition of what the arguments (parameters) ought to be on your BINOMIAL.DIST command.
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10/17/17
Jared L.
10/17/17