Concept:
If events are mutually independent, then:
\[
P(E_i\cap E_j)=P(E_i)P(E_j)
\]
and
\[
P(E_1\cap E_2\cap E_3)
=
P(E_1)P(E_2)P(E_3)
\]
We verify both statements individually.
Step 1: Check Statement I.
We need to test whether:
\[
E_1 \text{ and } (E_2\cup E_3)
\]
are independent.
We calculate:
\[
P(E_1\cap(E_2\cup E_3))
\]
Using distributive law:
\[
=
P((E_1\cap E_2)\cup(E_1\cap E_3))
\]
Applying addition theorem:
\[
=
P(E_1\cap E_2)+P(E_1\cap E_3)-P(E_1\cap E_2\cap E_3)
\]
Using mutual independence:
\[
=
P(E_1)P(E_2)+P(E_1)P(E_3)-P(E_1)P(E_2)P(E_3)
\]
Factorizing:
\[
=
P(E_1)\left[P(E_2)+P(E_3)-P(E_2)P(E_3)\right]
\]
But,
\[
P(E_2\cup E_3)
=
P(E_2)+P(E_3)-P(E_2)P(E_3)
\]
Hence,
\[
P(E_1\cap(E_2\cup E_3))
=
P(E_1)P(E_2\cup E_3)
\]
Therefore,
\[
E_1 \text{ and } (E_2\cup E_3)
\]
are independent.
Thus Statement I is TRUE.
Step 2: Check Statement II.
We need to verify whether:
\[
E_1 \text{ and } (E_2\cap E_3)
\]
are independent.
Now,
\[
P(E_1\cap(E_2\cap E_3))
=
P(E_1\cap E_2\cap E_3)
\]
Using mutual independence:
\[
=
P(E_1)P(E_2)P(E_3)
\]
Also,
\[
P(E_2\cap E_3)=P(E_2)P(E_3)
\]
Therefore,
\[
P(E_1)P(E_2\cap E_3)
=
P(E_1)P(E_2)P(E_3)
\]
Hence,
\[
P(E_1\cap(E_2\cap E_3))
=
P(E_1)P(E_2\cap E_3)
\]
Therefore,
\[
E_1 \text{ and } (E_2\cap E_3)
\]
are independent.
Thus Statement II is also TRUE.
Hence both statements are correct.
\[
\boxed{\text{Both I and II are true}}
\]