Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Let Z be a standard normal random variable and calculate the following probabili

ID: 3219104 • Letter: L

Question

Let Z be a standard normal random variable and calculate the following probabilities, drawing pictures wherever appropriate. (Round your answers to four decimal places.) (a) P(0 lessthanorequalto Z lessthanorequalto 2.37) (b) P(0 lessthanorequalto Z lessthanorequalto 2) (c) P(-2.60 lessthanorequalto Z lessthanorequalto 0) (d) P(-2.60 lessthanorequalto Z lessthanorequalto 2.60) (e) P(Z lessthanorequalto 1.64) (f) P(-1.95 lessthanorequalto Z) (g) P(-1.60 lessthanorequalto Z lessthanorequalto 2.00) (h) P(1.64 lessthanorequalto Z lessthanorequalto 2.50) (i) P(1.60 lessthanorequalto Z) (j) P(|Z| lessthanorequalto 2.50)

Explanation / Answer

a) P(0 < Z < 2.37) = P(Z < 2.37) - P(Z < 0)

                             = 0.9911 - 0.5

                             = 0.4911

b) P(0 < Z < 2) = P(Z < 2) - P(Z < 0)

                        = 0.9772 - 0.5

                        = 0.4772

c) P(-2.6 < Z < 0) = P(Z < 0) - P(Z < -2.6)

                             = 0.5 - 0.0047

                             = 0.4953

d) P(-2.6 < Z < 2.63) = P(Z < 2.63) - P(Z < -2.6)

                          = 0.9953 - 0.0047

                            = 0.9906

e) P(Z < 1.64) = 0.9495

f) P(Z > -1.95) = 1 - P(Z < -1.95)

                       = 1 - 0.0256

                       = 0.9744

g) P(-1.6 < Z < 2) = P(Z < 2) - P(Z < -1.6)

                             = 0.9772 - 0.0548

                             = 0.9224

h) P(1.64 < Z < 2.5) = P(Z < 2.5) - P(Z < 1.64)

                                = 0.9938 - 0.9495

                                = 0.0443

i) P(Z > 1.6) = 1 - P(Z < 1.6)

                    = 1 - 0.9452

                    = 0.0548

j) P(|Z| < 2.5) = P(-2.5 < Z < 2.5)

                      = P(Z < 2.5) - P(Z < -2.5)

                      = 0.9938 - 0.0062

                      = 0.9876