For these data, calculate the standard deviation, . Round to the nearest tenths place if a fraction. The standard deviation is: Answer

A.1.9

2

3.7

3.8

the standard deviation is a value not listed in alternatives "a" through "d"

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We have the mean (`barx` ) = `(2+2+7+4+4+7+2+2+3)/9` = `33/9` = `11/3`

For calculation of variance,

`x_i` `x_i-barx` `(x_i-barx)^2`

`2` `-5/3` `25/9`

`2` ` -5/3` `25/9 `

`7 ` `10/3` `100/9 `

`4` `1/3` `1/9`

`4` `1/3` `1/9`

`7` `10/3` `100/9`

`2` `-5/3` `25/9`

`2` `-5/3` `25/9`

`3` `-2/3` `4/9`

`Sigma(x_i-barx)^2 = 306/9 = 34`

Here, n=9 and `Sigma(x_i-barx)^2 = 34`

Hence Variance = `1/nSigma(x_i-barx)^2 = 34/9`

`rArr Standard Deviation = sqrt (Variance) = sqrt (34/9)`

`= sqrt34/3`

`= 1.9436506`

`= 1.9` (after rounding off to the nearest tenth place of a fraction)

**Hence the correct answer is option A) 1.9**

**Sources:**

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