document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1051295>Question 1051295</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can someone show me how to work these type of math questions? Please, check the ones I tried to do. Thank you for your help.\r<BR>\n" );
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document.write( "On the average, members at a local fitness center work out for 90 minutes with a standard deviation of 15 minutes. The distribution is normal.\r<BR>\n" );
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document.write( "a) What percentage of the fitness club members work out for 45 minutes or less?\r<BR>\n" );
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document.write( "b) What percentage of the fitness club members work out for 2 hours and 15 minutes or more?\r<BR>\n" );
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document.write( "c) 68% of the fitness club members work out between which two time intervals?\r<BR>\n" );
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document.write( "(Mean - std) and (Mean + std)<BR>\n" );
document.write( "(90 - 15) and (90 + 15)<BR>\n" );
document.write( "75 and 105\r<BR>\n" );
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document.write( "d) We can say that 99.7% of the fitness club members work out for no more than ____________ minutes.\r<BR>\n" );
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document.write( "(Mean - 3 × std) and (Mean + 3 × std) <BR>\n" );
document.write( "(90 - 3 × 15) and (90 + 3 × 15)<BR>\n" );
document.write( "45 and 135\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #666851 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=666851\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> On the average, members at a local fitness center work out for 90 minutes with a standard deviation of 15 minutes. The distribution is normal. \r<BR>\n" );
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document.write( "a) What percentage of the fitness club members work out for 45 minutes or less?<BR>\n" );
document.write( "z(45) = (45-90)/15 = -45/15 = -3<BR>\n" );
document.write( "P(x <= 45) = P(z <= -3) = normalcdf(-100,-3) = 0.0013<BR>\n" );
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document.write( "b) What percentage of the fitness club members work out for 2 hours and 15 minutes or more?<BR>\n" );
document.write( "z(135) = (135-90)/15 = 45/15 = 3<BR>\n" );
document.write( "P(x >= 135 min) = P(z >= 3) = 0.0013<BR>\n" );
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document.write( "c) 68% of the fitness club members work out between which two time intervals? <BR>\n" );
document.write( "(Mean - std) and (Mean + std)<BR>\n" );
document.write( "(90 - 15) and (90 + 15)<BR>\n" );
document.write( "75 and 105 \r<BR>\n" );
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document.write( "d) We can say that 99.7% of the fitness club members work out for no more than ____________ minutes. \r<BR>\n" );
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document.write( "(Mean - 3 × std) and (Mean + 3 × std) <BR>\n" );
document.write( "(90 - 3 × 15) and (90 + 3 × 15)<BR>\n" );
document.write( "45 and 135 <BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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