Question

Determine the are under the standard normal curve that lies to the left of a) z=-2.45 b) z=-0.43 c) z= 1.35 d) z= 3.49 I don't know how to do this on my Ti 84 . How do I do this by hand Thanks in advance

Answer 1

a)

We have to calculate P( Z < -2.45) = ?

P( Z < -2.45) = 1 - P( Z < 2.45)

= 1 - 0.9929 (Probability calculated using Z table)

= 0.0071

b)

P( Z < -0.43) = 1 - P( Z < 0.43)

= 1 - 0.6664 (Probability calculated using Z table)

= 0.3357

c)

P( Z < 1.35) = 0.9115 (Probability calculated using Z table)

d)

P( Z < 3.49) = 0.9998 (Probability calculated using Z table)  

[ From Ti-84 calculator, first two negative z-scores calculated by function

normalcdf{-0.99999,z}

Where -0.99999 is lowest value by default and z is z-score given in above parts.

Put z-score for each part in above function in Ti-84 and hit ANSWR,]