A random variable X has a mean of 120 and a standard deviation of 15 a random variable Y has a mean of 100 and a standard deviation of 9. if c and y are independent approximately what is the standard deviation of X plus Y

The standard deviation of X + Y is 17.5

The given parameters are:

--- the mean of X

-- the standard deviation of X

--- the mean of Y

--- the standard deviation of Y

The standard deviation of X + Y is then calculated as:

This gives

Evaluate the exponents

Take the square root of 306

Hence, the standard deviation of X + Y is 17.5

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The standard deviation is 17.5

Step-by-step explanation:

Let S be the sum of X and Y

S = X + Y

So we want to calculate the standard deviation of S

The standard deviation of S will be the square root of the sum of the variances of X and Y

Kindly recall that variance is the square of standard deviation

The variance of X will be 15^2 = 225

The variance of Y will be 9^2 = 81

So the standard deviation of the sum will be

√(81 + 225)

= √(306)

= 17.5

in simplified version   it would be x ≤-4

step-by-step explanation:

multiply each term in x ≤-4 by -1

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step-by-step explanation: