Q.Given that the mean of the data is \( 20.6 \), determine the value of \( a \).
\( x_i \)1015\( a \)2535
\( f_i \)3102575

Variable \((x_i )\)Frequency \((f_i )\)\((x_i f_i)\)
10330
1510150
\(a\)25\(25a\)
257175
355175
Total\(\sum f_i=50\)\(\sum x_i f_i=530+25a\)
\(\therefore\) According to the question, the mean is \( 20.6 \). \[ \cfrac{\sum x_i f_i}{\sum f_i} = 20.6 \] \[ \cfrac{530+25a}{50} = 20.6 \] \[ 530+25a = 1030 \] \[ 25a = 500 \] \[ a = 20 \]
Similar Questions