The mean of the following distribution is 52 and the frequency of class interval 30 - 40 is 'f'. Find 'f'. ClassIntervalFrequency10−20520−30330−40f40−50750−60260−70670−8013 [4 MARKS]
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Solution
Formula: 2 Marks Solution: 2 Marks
ClassFrequencyxfxIntervale(f)10−205157520−303257530−40f3535f40−5074531550−6025511060−7066539070−801375975∑f=25∑fx=1940+35f ∴ Mean =∑fx∑f ⇒52=1940+35f36+f ⇒1872+52f=1940+35f ⇒17f=1940−1872 ⇒17f=68⇒f=4