iv) Area from 2.18 to  1.35 is the same from 1.35 to 2.18.
P ( 2.18 £
z £
1.35 ) = 0.4854  0.4115
= 0.0739 i.e. »
7% of area.
v) Required area = 0.5  Area between z = 0 to z = 0.6 (to the left of 0.6)
= 0.5  P ( o
£
z £
0.6 )
= 0.5  ( 0.2257 )
= 0.2743 »
27% of area.
vi) Required area = (Area between z = 0 and z = 1.28) + 0.5
=
(Area between z = 0 and z = 1.28) + 0.5
=
0.3997 + 0.5
=
0.8997 » 90% of area.
vii) Area from  2.18 to 0 is the same as
from 0 to 2.18 which is
P ( 2.18 £ z £ 0 )
= P ( 0 £ z £ 2.18) = 0.4864
and area from 0 to 1.35 is
P ( 0 £ z £ 1.35) = 0.4115
Thus the required area is the sum of two
i.e. P (2.18 £ z £ 1.35) = 0.4854 + 0.4115
= 0.8969 » 90% of area
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