document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=930943>Question 930943</A>: <I><SPAN STYLE=\"word-break: break-all;\"> it is known that 80% of all college professors have doctoral degree. if 10 professors are randomly selected find the probability that<BR>\n" );
document.write( "a: fewer than 4 have doctoral degree<BR>\n" );
document.write( "b: at least 6 have doctoral degree<BR>\n" );
document.write( "c: between 5 and 7 (inclusive) have doctoral degree<BR>\n" );
document.write( "  <BR>\n" );
document.write( "   please help me to understand it step by step .Thank u :) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #565352 by </B><A HREF=/tutors/aboutme.mpl?userid=ewatrrr><B>ewatrrr(24785)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ewatrrr><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=ewatrrr><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=565352\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> n(doc degree) = .80 ,  n = 10<BR>\n" );
document.write( "....<BR>\n" );
document.write( "Using a TI calculator 0r similarly a Casio fx-115 ES plus<BR>\n" );
document.write( "P(x < 4)= binomcdf(10, .80, 3) = .00086<BR>\n" );
document.write( "......<BR>\n" );
document.write( "P(x &#8805; 6) = 1 - binomcdf(10, .80, 5)= 1-.0328 = .9672<BR>\n" );
document.write( "..........<BR>\n" );
document.write( "P(5&#8804; x &#8804; 7) = binomcdf(10, .80, 7) - [ 1- binomcdf(10, .80, 4)]<BR>\n" );
document.write( "P(5&#8804; x &#8804; 7) = .3222 - .0064 = .3158<BR>\n" );
document.write( "0r<BR>\n" );
document.write( "P(5&#8804; x &#8804; 7) = P(x=5) + P(x=6) + P(x=7) = .0264 + .0881 + .2013 = .3158<BR>\n" );
document.write( "Using binompdf()  Or for ex P(x=5) = 10C5(.8)^5(.2)^5<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );