So here is the problem:

" The mean of a random variable, x, is 19 and its variance is 5. What is the mean, variance and standard deviation of y where y=7x-2? "

I'm new to random variable statistics, so I'm having trouble understanding how a variable x can have a mean and a variance...

Thanks!

If the random variable X has mean and variance , then the random variable Y = aX + b has mean , variance and standard deviation .

In your question a = 7 and b = -2.

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