Question

Use the z-table to find the requested probabilities. Enter your answers to 4 decimal places. (a) P(z < 2.97) = (b) P(z ? ?2.34) = (c) P(?2.37 < z < 1.99) =

Answer 1

olution :
Using standard normla table,
a )P(Z < 2.97)  
To see the z value 0.2 in the column and 0.97 in the row of the standard normal table the corresponding probability is
Probability = 0.9985

b )P(Z - 2.34)  

= 1 - P(Z - 2.34)
To see the z value - 0.2 in the column and 0.34 in the row of the standard normal table the corresponding probability

= 1 - 0.0096

= 0.9904
Probability = 0.09904

c ) P(?2.37 < z < 1.99)

P( z < 1.99 ) - P ( z < - 2.37 )

= 0.9767 - 0.0089

= 0.9678

Probability = 0.9678