document.write( "Question 1039303: Find out arithmetic mean from the following data by step deviation method:
\n" ); document.write( "Marks |Frequency
\n" ); document.write( "12.5-17.5 | 4
\n" ); document.write( "17.5-22.5 | 20
\n" ); document.write( "22.5-27.5 | 17
\n" ); document.write( "27.5-32.5 | 15
\n" ); document.write( "32.5-37.5 | 2
\n" ); document.write( "37.5-42.5 | 5
\n" ); document.write( "42.5-47.5 | 5
\n" ); document.write( "47.5-52.5 | 2 \n" ); document.write( "

Algebra.Com's Answer #654988 by robertb(5830) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let the class interval 27.5 - 32.5 be the zero basis for the step deviation.
\n" ); document.write( "Note that the class mark for the basis class interval is 30, and the class width is 5.\r
\n" ); document.write( "\n" ); document.write( "d | f | df
\n" ); document.write( "----------------
\n" ); document.write( "-3 | 4 | -12
\n" ); document.write( "-2 | 20 | -40
\n" ); document.write( "-1 | 17 | -17
\n" ); document.write( "0 | 15 | 0
\n" ); document.write( "1 | 2 | 2
\n" ); document.write( "2 | 5 | 10
\n" ); document.write( "3 | 5 | 15
\n" ); document.write( "4 | 2 | 8
\n" ); document.write( "----------------
\n" ); document.write( " | 70 |-34\r
\n" ); document.write( "\n" ); document.write( "==> Mean = $\"30%2Bsum%28df%2C+i=1%2C8%29%2FN+=+30+%2B+%28-34%2F70%29%2A5+=+193%2F7\"$ , or about 27.57. \n" ); document.write( "

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