2 . The following table shows the times x ( in hours ) of six students spending on revision and the corresponding test results y ( in marks ).
Revision time ( x hours ) 1.5 3.5 5 5.5 6 7.5 Test result ( y marks ) 60 75 85 75 70 75
It is suggested that the relationship between the variables can be modelled by the regression equation y � � x � x � .
2
1.15 12.5 45
( a ) Use the suggested model to write down the estimated test result of a student when the revision time spent by the student is
( i ) 3.5 hours ;
( ii ) 5.5 hours ;
( iii ) 7.5 hours ,
giving the answers in exact values .
( b ) Hence , calculate SS res
, the sum of square residuals .
It is given that the coefficient of determination of this model is 0.632 .
[ 3 ]
[ 2 ]
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( c ) Interpret the coefficient of determination . [ 1 ] www . seprodstore . com
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