In: Statistics and Probability
Find the following probabilities for the standard normal random variable z z :
a) P(−2.07≤z≤1.93)= P ( − 2.07 ≤ z ≤ 1.93 ) =
(b) P(−0.46≤z≤1.73)= P ( − 0.46 ≤ z ≤ 1.73 ) =
(c) P(z≤1.44)= P ( z ≤ 1.44 ) =
(d) P(z>−1.57)= P ( z > − 1.57 ) =
Solution:
Given that,
Using standard normal table;
(a)
P(-2.07 z 1.93)
= P(z 1.93) - P(z -2.07)
= 0.9732 - 0.0192
= 0.954
P(-2.07 z 1.93) = 0.954
(b)
P(-0.46 z 1.73)
= P(z 1.73) - P(z -0.46)
= 0.9582 - 0.3228
= 0.6354
P(-0.46 z 1.73) = 0.6354
(c)
P(z 1.44) = 1 - P(z 1.44) = 1 - 0.9251 = 0.0749
(d)
P(z > -1.57) = 1 - P(z < -1.57) = 1 - 0.0582 = 0.9418