Question 1206637
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Consider a binomial random variable with n = 7 and p = 0.8. 
Let x be the number of successes in the sample. Evaluate the probability. 
(Round your answer to three decimal places.)
P(x = 3)
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Use the standard formula for the binomial distribution probability,
which you should know from your textbook, since it is a pre-requisite


    P = {{{C[7]^3*0.8^3*(1-0.8)^(7-3)}}} = {{{((7*6*5)/(1*2*3))*0.8^3*0.2^4}}} = 0.028672.


<U>ANSWER</U>.  P = 0.029, rounded as requested.



Alternatively, you can use a regular calculator TI-83/84, with its standard function binompdf.

To learn about it and HOW TO, read from this source

https://www.sayvilleschools.org/site/handlers/filedownload.ashx?moduleinstanceid=3050&dataid=12830&FileName=calc%20directions.pdf



Alternatively, you can use Excel standard function BINOM.DIST

About this function, its format and parameters/arguments, read from this source 

https://support.microsoft.com/en-us/office/binom-dist-function-c5ae37b6-f39c-4be2-94c2-509a1480770c



Alternatively, you can use free of charge online calculator 

https://stattrek.com/online-calculator/binomial.aspx

which, in my opinion, is the best tool for such calculations/exercises.
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Solved.