question please help me with these thanks alotSolution 1 a P

question

please help me with these ..thanks alot

Solution

1)

a)

P(Z>-0.09) = 1 - norm(-0.09) = 0.5359

b) P(0.53 < Z < 1.24) = norm(1.24) - norm(0.53) = 0.1906

c) P(-0.54 < Z < 0.05) = norm(0.05) - norm (-0.54) = 0.2253

2)

a)

P(X <58) = P(Z < 58 - 50 / 9) = P( Z < 0.8889) = 0.8130

b)

P(X >35) = P(Z > 35 - 50 /9) = P(Z > -1.66667) = 0.9522

3)

P(X >65) = P(Z > 65 - 75 /8) = P(Z > -1.25) = 0.8944

so number of students scored higher than 65 = 0.8944 * 100 = 90 students