Q.If \(∑f_i d_i = 400\), \(∑f_i = 50\), and \(a =\) assumed mean \(= 52\), then the value of the combined mean is – (a) 52 (b) 60 (c) 80 (d) 55
Answer: B
The calculated mean \(= a + \cfrac{∑f_i d_i}{∑f_i}\)
\(= 52 + \cfrac{400}{50} = 52 + 8 = 60\)
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