Is the standard deviation of the set of measurements x1, x2, x3....x20 less than 3?
A) The variance for the set of measurements is 4.
B) For each measurement, the difference between the mean and that measurement is 2.
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Standard deviation of a set
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liferocks
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variance of a set=average of square root of difference between the mean and that measurements
and standard deviation=square root of variance
since both conditions provides the variance either is sufficient
Hence ans D
and standard deviation=square root of variance
since both conditions provides the variance either is sufficient
Hence ans D
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liferocks
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You can get a detail definition here https://en.wikipedia.org/wiki/Varianceduongthang wrote:pls, help
what is variance?
in simple word for a series
x1,x2,x3.. if mean is x
variance =[(x-x1)^2+(x-x2)^2+(x-x3)^2]/3
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ajith
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Variance in this Example is if mean is mpkw209 wrote:Is the standard deviation of the set of measurements x1, x2, x3....x20 less than 3?
A) The variance for the set of measurements is 4.
B) For each measurement, the difference between the mean and that measurement is 2.
(m-x1)^2+(m-x2)^2 ......+ (m-x20)^2)/20
Standard deviation is the square root of the variance.
a) Variance =4 ; SD = 2
b) Variance = (2^2+2^2.....+2^2)/20 = 2^2 = 4; SD = 2
A and B are independently sufficient! D
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gmatmachoman
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@ajith bhai,ajith wrote:Variance in this Example is if mean is mpkw209 wrote:Is the standard deviation of the set of measurements x1, x2, x3....x20 less than 3?
A) The variance for the set of measurements is 4.
B) For each measurement, the difference between the mean and that measurement is 2.
(m-x1)^2+(m-x2)^2 ......+ (m-x20)^2)/20
Standard deviation is the square root of the variance.
a) Variance =4 ; SD = 2
b) Variance = (2^2+2^2.....+2^2)/20 = 2^2 = 4; SD = 2
A and B are independently sufficient! D
I thought u r gone with the wind!! Bhai i was missing u ...as i had some doubts in set theory..luckily LR bhai chipped in and solved couple of them..
@LR thanks..
