Question

find the variance of 3x + 2 if standard deviation of x is 4.​

Answer 1

Answer:

the var(ax+b)=3²×16

=9×16

=144

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Answer 2

Given,

The standard deviation of x is 4.

To Find,

The variance of 3x + 2.

Solution,

To find the variance, we will follow the following steps:

The random variable 3x+2 is written as 3a+b.

Then variance is given by the formula:

The variance of 3x+2 = a²× (variance of a random variable x)

The variance of 3x +2 = 3²×(standard deviation of a random variable x)²

The variance of 3x +2 = 9 × 16

The variance of 3x +2 = 144

Henceforth, the variance of 3x+2 is 144.