Ex 13.1, 3 - Chapter 13 Class 10 Statistics

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Ex 13.1, 3 The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs.18. Find the missing frequency f. Mean(𝑥 ̅) = a + (∑▒𝒇𝒊𝒅𝒊)/(∑▒𝒇𝒊) Where a = Assumed Mean h = Class interval Putting values in formula Mean = 18 + (2𝑓 − 40)/(44 + 𝑓) 18 = 18 + (2𝑓 − 40)/(44 + 𝑓) 18 − 18 = (2𝑓 − 40)/(44 + 𝑓) 0 = (2𝑓 − 40)/(44 + 𝑓) 0 = 2𝑓−40 2𝑓=40 f = 40/2 f = 20