document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=764227>Question 764227</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Statistic question\r<BR>\n" );
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document.write( "A psychology professor gives a surprise quiz consisting of 10 true/false questions, and she states that passing requires at least 7 correct responses. Assume that an unpreprated student adopts the questionable strategy of guessing for each anser.<BR>\n" );
document.write( "a. find the probability that the first 7 responses are correct and the last 3 are wrong.\r<BR>\n" );
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document.write( "b. is the probability from part a equal to the probability of passing? why or why not?\r<BR>\n" );
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document.write( "Please help!!!<BR>\n" );
document.write( "Thank you. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #465305 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=465305\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If one is guessing, then the probability of getting a correct answer is 1/2 and the probability of getting an answer wrong is also 1/2.<BR>\n" );
document.write( "Probability that the first 7 answers are correct is (1/2)^7 = .008<BR>\n" );
document.write( "Probability that the last three answers are false is (1/2)^3 = .125<BR>\n" );
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document.write( "a)  sum the two probabilities, .008 + .125 = .133<BR>\n" );
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document.write( "b) answer is no - because there are multiple ways to get 7 answers correct when guessing:<BR>\n" );
document.write( "there are 7 ways to get a passing grade by guessing<BR>\n" );
document.write( "   7        0        0        3<BR>\n" );
document.write( "   6        1        1        2<BR>\n" );
document.write( "   5        2        2        1   <BR>\n" );
document.write( "   4        3        3        0<BR>\n" );
document.write( "   3        1        4        2<BR>\n" );
document.write( "   2        2        5        1<BR>\n" );
document.write( "   1        3        6        0<BR>\n" );
document.write( "multiply 7 times .008 = .056\r<BR>\n" );
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document.write( " </SPAN>\n" );
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