document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=880843>Question 880843</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A study has shown that 20% of all university textbooks have a price greater than or equal to £40. It is known that the standard deviation of the prices of all university textbooks is £6. If the prices of all university textbooks follow a normal distribution, then work out the average (mean) price. </SPAN>\n" );
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document.write( "z = invNorm(.80) = (x-bar-40)/6<BR>\n" );
document.write( "6invNorm(.80)+ 40 =  x-bar </SPAN>\n" );
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