"Should": advisability or expectation

I know 'should' has two primary meanings showing advisability or expectation. But sometimes I am confused without the context. Please look at the sentences below.

1.She should do well on the test.
She should have done well on the test.

2. The letter should have been sent last week.

3.James should have been told the news a long time ago.

4.The class should be divided in half.

Do we know what the 'shoulds' in the sentences mean without additional contexts?

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