Statistics

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Mean (x̄) = Σfixi / Σfi, where fi is the frequency of each class and xi is the class mark (mid-point) of each class interval.

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Class mark (xi) is the mid-point of a class interval. It is calculated as: Class mark = (Lower limit + Upper limit) / 2. For example, for class interval 20-30, class mark = (20+30)/2 = 25.

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Mean (x̄) = a + (Σfidi / Σfi), where 'a' is the assumed mean (usually a class mark), di = xi - a (deviation of each class mark from assumed mean), and fi is the frequency.

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Mean (x̄) = a + (Σfiui / Σfi) × h, where 'a' is assumed mean, ui = (xi - a) / h, h is class size, and fi is frequency. This method simplifies calculations when class intervals are equal.

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Mode of grouped data is the value that occurs most frequently. Unlike ungrouped data where we can directly identify the most frequent value, in grouped data we use a formula to find the mode within th…

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Mode = l + [(f1 - f0) / (2f1 - f0 - f2)] × h, where l = lower limit of modal class, f1 = frequency of modal class, f0 = frequency of class before modal class, f2 = frequency of class after modal class…

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The modal class is the class interval with the highest frequency. It is the class where the mode lies and is used in the mode formula for grouped data.

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Cumulative frequency of a class is the total frequency obtained by adding the frequencies of all classes up to and including that class. It shows how many observations fall below the upper limit of ea…