document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1115800>Question 1115800</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The mean test score for a class was 70 points, and the standard deviation was 15 points. If I add 10 points to everyone's test score..<BR>\n" );
document.write( "(a) What is the mean  test score for the class after I add the 10 points to each score?<BR>\n" );
document.write( "(b) What is the standard deviation of the test scores for the class after I add the 10 points to each score? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #730697 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=730697\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> i believe the mean will be 80 and the standard deviation will remain at 15.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "a simple experiment indicates that this will be the case.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "assume 3 numbers, for example:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "50<BR>\n" );
document.write( "100<BR>\n" );
document.write( "150\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the mean will be 50 + 100 +150 = 300 / 3 = 100\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the standard deviation will be (50-100)^2 + (100-100)^2 + (150-100)^3 = 2500 + 0 + 2500 = 5000/3 = 1666 and 2/3\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "add 10 points to everybody's score.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the scores becomes:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "60<BR>\n" );
document.write( "110<BR>\n" );
document.write( "160\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the mean is 60 + 110 + 160 = 330 / 3 = 110\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the standard deviation is (60 - 110)^2 + (110-110)^2 + (160-110)^2 = 2500 + 0 + 2500 = 5000 / 3 = 1666 and 2/3.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the mean was raised by 10 and the standard deviation stayed the same.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "here's an excel printout that shows the same thing.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the numbers were randomly generated by excel.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "then the mean and the standard deviation were calculated for both the original data set and the data set where each element was raised by 10.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the mean was 10 greater and the standard deviation remained the same.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" src = \"http://theo.x10hosting.com/2018/042601.jpg\" alt=\"$$$\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );