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If the mean and the mode of a particular data set are 36 and 63, respectively, then, using an empirical relation, find the value of the median of the same data set.
55
45
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39
45
Use the relationship Median=3Mode+2├ЧMeanтАЛ. With given values: (63+72)/3=135/3=45.
Mean = 36, Mode = 63
Mode=3├ЧMedianтИТ2├ЧMean
Use the relationship Median=3Mode+2├ЧMeanтАЛ. With given values: (63+72)/3=135/3=45.
Students often misremember the empirical relation as Mode=3├ЧMeanтИТ2├ЧMedian or Mode=2├ЧMedianтИТ3├ЧMean, which leads to incorrect answers.
State the empirical formula
The empirical relationship between Mean, Median, and Mode for a moderately skewed distribution is given by the formula:
Mode=3├ЧMedianтИТ2├ЧMean
Substitute the known values
Substitute Mean=36 and Mode=63 into the equation:
63=3├ЧMedianтИТ2├Ч36
Simplify and solve for Median
First calculate 2├Ч36=72, then add it to both sides: 63+72=3├ЧMedian, which simplifies to 135=3├ЧMedian. Dividing by 3 gives the median:
Median=3135тАЛ=45
B is correct because calculating the median using the empirical relation Mode=3├ЧMedianтИТ2├ЧMean yields Median=45.
This empirical relation is a classic frequent topic in RRB exams. Remember the '3-2-1' rule: Mode=3(Median)тИТ2(Mean).