Question

Find Mean, median, varianca and standard deviation for:
6, 10, 18, 25, 13, 16, 11, 7, 11.

Answer 1

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first arrange the data in ascending order

6 , 7 , 10 , 11 , 11 , 13 , 16 , 18 , 25.

The median is the number halfway(or middlemost) into our data.

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there are 2 types of Variance and  standard deviation

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first one is "sample" and other one is "population"

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for sample

here mean m=13

(10-13)² = 9
(11-13)² = 4
(11-13)² = 4
(13-13)² = 0
(16-13)² = 9
(18-13)² = 25
(25-13)² = 144
(6-13)² = 49
(7-13)² = 36.

Add all these numbers above
9+4+4+0+9+25+144+49+36=280

total 9 numbers so n=9

..............variance (For a sample)

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.............. standard deviation (For a sample)

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for population

here mean m=13

(10-13)² = 9
(11-13)² = 4
(11-13)² = 4
(13-13)² = 0
(16-13)² = 9
(18-13)² = 25
(25-13)² = 144
(6-13)² = 49
(7-13)² = 36.

Add all these numbers above
9+4+4+0+9+25+144+49+36=280

total 9 numbers so n=9

..............variance (For a population)

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.............. standard deviation (For a population)