In: Statistics and Probability
Let X be normally distributed with mean μ = 18 and standard deviation σ = 8. [You may find it useful to reference the z table.]
a. Find P(X ≤ 2). (Round
"z" value to 2 decimal places and final
answer to 4 decimal places.)
b. Find P(X > 4).
(Round "z" value to 2 decimal places and final
answer to 4 decimal places.)
c. Find P(8 ≤ X ≤ 16).
(Round "z" value to 2 decimal places and final
answer to 4 decimal places.)
d. Find P(12 ≤ X
≤ 22). (Round "z" value to 2 decimal
places and final answer to 4 decimal places.)
a)
= P(Z < -2)
= 0.0228
b)
= P(Z > -1.75)
= 1 - P(Z < -1.75)
= 1 - 0.0401
= 0.9599
c)
= P(-1.25 < Z < -0.25)
= P(Z < -0.25) - P(Z < -1.25)
= 0.4013 - 0.1056
= 0.2957
d)
= P(-0.75 < Z < 0.5)
= P(Z < 0.5) - P(Z < -0.75)
= 0.6915 - 0.2266
= 0.4649