document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=209316>Question 209316</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose there are 10 items on a true-false quiz. The person taking the test does not read the questions; he just answers the questions randomly. What is the probability of his guessing all answers correctly?<BR>\n" );
document.write( "How should I find out how many answers he answered correctly??  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #158359 by </B><A HREF=/tutors/aboutme.mpl?userid=MathTherapy><B>MathTherapy(10555)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathTherapy><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=MathTherapy><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=158359\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Suppose there are 10 items on a true-false quiz. The person taking the test does not read the questions; he just answers the questions randomly. What is the probability of his guessing all answers correctly?<BR>\n" );
document.write( "How should I find out how many answers he answered correctly?? \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Since we're trying to find out a specific number of successes, 10, based on the probability of success, and probability of failure, we just use the binomial probability formula, which states:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "P(s successes in n trials) = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=_%5Bn%5DC%5Bs%5D%2Ap%5Es%2Aq%5E%28n-s%29 ALIGN=MIDDLE  ALT=\"_%5Bn%5DC%5Bs%5D%2Ap%5Es%2Aq%5E%28n-s%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >, where:\r<BR>\n" );
document.write( "\n" );
document.write( "n = number of trials ; s = number of successes ; p = probability of success, and q = probability of failure\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Applying the formula, we get: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=_%5B10%5DC%5B10%5D%2A.5%5E10%2Aq%5E%2810-10%29 ALIGN=MIDDLE  ALT=\"_%5B10%5DC%5B10%5D%2A.5%5E10%2Aq%5E%2810-10%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "=  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1+%2A+.5%5E10+%2A+1 ALIGN=MIDDLE  ALT=\"1+%2A+.5%5E10+%2A+1\"   DISABLED_style= \"max-width:90%; height:auto;\" >  =  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%280.000977%29 ALIGN=MIDDLE  ALT=\"highlight_green%280.000977%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );