Using the Standard Normal Table, determine the following:

Question

a) P(z< -1.24)

b)P(z < -3.01)

c)P(z ≥ 2.21)

d) P( -0.36 ≤ z ≤ 1.11)

e) P( -0.75 ≤ z ≤ 0.75)

Answer 1

P( z<-1.24) = 0.10749 = 10.749%

P( z<-3.01) = .0013062 =0.13062%

P(z>2.21) = .01353 = 1.3553%

P(-.36 < z < 1.11) =.50708 = 50.708%

P(-.75 < z < 75) = .54675 = 54.675%

using the empirical rule on P(z<3.01) gives P(z<3) = (1-.997)/2 = .003/2= .0015

which is a close approximation, and with 3.01 you would expect to get a slighly smaller

percentage than .0015. It's also a check on whether you're reading the tables correctly.

Or also, use a calculator with statistics functions, such as desmos online's z calculator