Marks of 12 students in a unit test are given as 1,2,3,4,5,6,7,8,9,10,11,12.Assume a mean and calculate the arithmetic mean of the data.Assume another number as mean and calculate the arithmetic mean again.Do you get the same result? comment
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Answer:
Let assumed mean be 13
∴ Arithmetic mean =13+
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12
(4−13)+(21−13)+(13−13)+(17−13)+(5−13)+(9−13)+
(10−13)+(20−13)+(19−13)+(12−13)+(20−13)+(14−13)
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=13+
12
8
=13+0.67
=13.67
Now let assumed mean be 14
∴ Arithmetic mean =14+
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14
(4−14)+(21−14)+(13−14)+(17−14)+(5−14)+(9−14)+
(10−14)+(20−14)+(19−14)+(12−14)+(20−14)+(14−14)
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=14+[
12
−4
]=13.67
Yes, 9 got the same result.
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