- #1
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Homework Statement
Assume X is normally distributed with a mean of 10 and a standard deviation of 2. Determine the value for x that solves P(-x < X - 10 < x) = 0.95
Homework Equations
P(X < x) = P(Z < z) = P(Z < (x - mean)/stdev)
The Attempt at a Solution
P(10 -x < X < 10 + x) = 0.95
P(X < 10 + x) - P(X < 10 - x) = 0.95
P(Z < (10+x-10)/2) - P(Z < (10-x-10)/2) = 0.95
P(Z < x/2) - P(Z < -x/2) = 0.95
That's as far as I get, and then I don't know what to do next, or if what I did was correct.