document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=468534>Question 468534</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am begging a tutor to show me how to do these hard homework problems.\r<BR>\n" );
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document.write( "The probability of winning is 0.45 every time you play a certain game. Suppose you play the game 10<BR>\n" );
document.write( "times. <BR>\n" );
document.write( "1. (1 point) Find the probability that you will win exactly 4 times. Round answer to three places after the<BR>\n" );
document.write( "decimal point.\r<BR>\n" );
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document.write( "I used the formula Pr(x-k)= c(n,k) p^k x q^ (n-k)\r<BR>\n" );
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document.write( "so... c(10,4) (.45)^4 x (.55)^(10-4)?\r<BR>\n" );
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document.write( "2. (1 point) Find the probability that you will win 2 or more times. Round answer to three places after<BR>\n" );
document.write( "the decimal point.\r<BR>\n" );
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document.write( "c(10,2) x (.45)^2 x (.55)^(8)?\r<BR>\n" );
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document.write( "3. (1 point) Find the expected number of times you will win, and the standard deviation. Round both<BR>\n" );
document.write( "answers to three places after the decimal point.\r<BR>\n" );
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document.write( "I dont even know how to set this one up...<BR>\n" );
document.write( "I think my biggest issue is understanding how to find k </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #321495 by </B><A HREF=/tutors/aboutme.mpl?userid=Tatiana_Stebko><B>Tatiana_Stebko(1539)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Tatiana_Stebko><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Tatiana_Stebko><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=321495\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 1. (1 point) Find the probability that you will win exactly 4 times. Round answer to three places after the decimal point. <BR>\n" );
document.write( "I used the formula Pr(x-k)= c(n,k) p^k x q^ (n-k) <BR>\n" );
document.write( "so... c(10,4) (.45)^4 x (.55)^(10-4) - CORRECT<BR>\n" );
document.write( "2. (1 point) Find the probability that you will win 2 or more times. Round answer to three places after the decimal point. <BR>\n" );
document.write( "P(win 2 or more times)=P(2)+P(3)+P(4)+P(5)+P(6)+P(7)+P(8)+P(9)+P(10)<BR>\n" );
document.write( "The best way to solve this problem by opposite event<BR>\n" );
document.write( "P(win 2 or more times)=1-P(win less then 2)<BR>\n" );
document.write( "P(win less then 2)=P(0)+P(1)<BR>\n" );
document.write( "THEN <BR>\n" );
document.write( "P(win 2 or more times)=1-(P(0)+P(1))<BR>\n" );
document.write( "P(win 2 or more times)=1-(c(10,0)(.45)^0*(.55)^(10-0)+c(10,1)(.45)^1*(.55)^(10-1))<BR>\n" );
document.write( "3.(1 point) Find the expected number of times you will win, and the standard deviation. Round both answers to three places after the decimal point. <BR>\n" );
document.write( "E(X)=np<BR>\n" );
document.write( "n=10, p=0.45<BR>\n" );
document.write( "E(X)=10*0.45=4.5<BR>\n" );
document.write( "the standard deviation<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%28X%29=sqrt%28n%2Ap%2A%281-p%29%29 ALIGN=MIDDLE  ALT=\"S%28X%29=sqrt%28n%2Ap%2A%281-p%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%28X%29=sqrt%2810%2A0.45%2A0.55%29=sqrt%282.475%29=1.573 ALIGN=MIDDLE  ALT=\"S%28X%29=sqrt%2810%2A0.45%2A0.55%29=sqrt%282.475%29=1.573\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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