document.write( "Question 74693This question is from textbook Elementary Statistics
\n" ); document.write( ": In a recent survey, 66% of the community favored building a police substation in their neighborhood. If 14 citizens are chosen, find the probability that exactly 11 of them favor the building of the police substation. \n" ); document.write( "
Algebra.Com's Answer #53679 by funmath(2933)\"\" \"About 
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In a recent survey, 66% of the community favored building a police substation in their neighborhood. If 14 citizens are chosen, find the probability that exactly 11 of them favor the building of the police substation.
\n" ); document.write( ":
\n" ); document.write( "This is a binomial probability problem.
\n" ); document.write( "The formula for that is:
\n" ); document.write( "\"highlight%28P%28x%29=%28n%21%2F%28%28n-x%29%21x%21%29%29%2Ap%5Ex%2Aq%5E%28n-x%29%29\" for x=0,1,2,...,n
\n" ); document.write( "Where:
\n" ); document.write( "n=number of trials
\n" ); document.write( "x=number of successes among n trials
\n" ); document.write( "p=probability of success in any one trial
\n" ); document.write( "q=probability of failure in any one trial (q=1-p)
\n" ); document.write( ":
\n" ); document.write( "! is a factorial symbol that denotes the product of descending numbers, like this:
\n" ); document.write( "4!=4*3*2*1 If your in a statistics class you probably have a calculator with the ! symbol available some where. For the TI 83 to TI 84, hit [MATH] arrow right>>> to PRB it's 4:!.
\n" ); document.write( ":
\n" ); document.write( "Some teachers allow you to shorten the formula to:
\n" ); document.write( "P(x)=[n]C[r]*p^x*q^(n-x)
\n" ); document.write( "r=x=number of successes among n trials.
\n" ); document.write( "All of the other symbols are the same as the first formula. If you're one of those, then you should know how to do it with your calculator.
\n" ); document.write( ":
\n" ); document.write( "I'm going to show you with the first formula.
\n" ); document.write( "p=66/100=.66
\n" ); document.write( "q=1-p=1-.66=.34
\n" ); document.write( "n=14
\n" ); document.write( "x=11
\n" ); document.write( "
\n" ); document.write( "\"P%2811%29=%2814%21%2F%283%21%2A11%21%29%29%2A%28.66%29%5E11%2A%28.34%29%5E3\"
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\n" ); document.write( "
\n" ); document.write( "\"P%2811%29=%2814%2A13%2A2%29%28.0103510234%29%28.039304%29\"
\n" ); document.write( "\"P%2811%29=.148088531\"
\n" ); document.write( "Round to whatever your teacher wants, most don't require more than 4 decimal spots.
\n" ); document.write( "\"highlight%28P%2811%29=.1481%29\"
\n" ); document.write( ":
\n" ); document.write( "I don't know how much work your teacher needs to see. If they only want an answer, then....
\n" ); document.write( "If you have a TI 83 to TI 84, these can be done by following these steps:
\n" ); document.write( "[2nd] [VARS] arrow down to 0:binompdf [ENTER]
\n" ); document.write( "type in [n] [,] [p] [,] [x] [)] [ENTER]
\n" ); document.write( "In this case it will look like binompdf(14,.66,11)=.1480885312
\n" ); document.write( ":
\n" ); document.write( "Look the instructions up for the calculator that you're using if it's not a TI 83 or 84.
\n" ); document.write( "Happy Calculating!!!!
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