Answer:
a)P [ z > 1,38 ] = 0,08379
b) P [ 1,233 < z < 2,43 ] Â = 0,1012
c) Â P [ z > -2,43 ] Â = 0,99245
Step-by-step explanation:
a) P [ z > 1,38 ] = 1 - Â P [ z < 1,38 ]
From z-table  P [ z < 1,38 ] = 0,91621
P [ z > 1,38 ] = 1 - 0,91621
P [ z > 1,38 ] = 0,08379
b)  P [ 1,233 - 2,43 ]  must be  P [ 1,233 < z < 2,43 ]
P [ 1,233 < z < 2,43 ] Â = P [ z < 2,43 ] - P [ z > 1,233 ]
P [ z < 2,43 ] Â = 0,99245
P [ z > 1,233 ] = 0,89125   ( approximated value  without interpolation)
Then
P [ 1,233 < z < 2,43 ] Â = 0,99245 - 0,89125
P [ 1,233 < z < 2,43 ] Â = 0,1012
c) P [ z > -2,43 ]
Fom z-table
P [ z > -2,43 ] = 1 - P [ z < -2,43 ]
P [ z > -2,43 ] = 1 - 0,00755
P [ z > -2,43 ] Â = 0,99245