A fact is a statement that can be verified. It may involve numbers or dates.
The truth of a fact is beyond argument.

Example: There are 24 people registered for English 152, Section 3, this summer.

Example: A football field in the US is 100 yards long.

Example:Helen Hayes, the First Lady of the American Theatre, died on March 17, 1993, at 92 years of age.

Expressions of personal likes or dislikes are erroneously often called opinions.

Example: Dawn feels sports medicine is the field to be in.

Example: I like chicken fat ripple ice cream.

Example: Lisa enjoys jazz more than rock music.

Example: My husband looks great in the nude.

An opinion is an informed judgment based on facts, an honest attempt to draw a reasonable conclusion from evidence.

It is arguable--a contestable statement.

Given the same truthful information, another person may come up with a different conclusion (opinion).

Example:Because the Cold War is over, we should dismantle the US defense forces.

we should scale back the US defense forces.

we can now concentrate on aggressively controlling Third World despots with US defense forces.

An arguable opinion, then, needs

•  a thesis statement, a claim, a proposition to be supported, which deals with a matter of probability, not a fact or a matter of taste. [In other words, "What's your point?"]
  
  
• an audience to be convinced of the thesis
  
  
• grounds, specific reasons, that support the thesis.

Here's a test to see (hear, feel) whether you have an opinion:

"What makes you say (write) that?"

If the answer reverts to "I" something-or-other, then it is not an opinion, but a statement of taste. [And there's no accounting for taste.]

A writer (speaker, doer) implies.

A reader (listener, onlooker) infers.

To imply means

• to convey or communicate not by direct, forthright statement but by allusion or reference likely to lead to natural inference.
  
  
• to express indirectly
  
  
• to involve or suggest by logical necessity.

["What are you suggesting (implying)?]

To infer means

• to conclude from evidence; deduce
  
  
• to have as a logical consequence. (an inference = a conclusion)

Example: I see leaves turning yellow on a small tree. I know it is July 11th in the middle of the summer. It hasn't rained in 2 months. I infer (deduce, conclude) [through inference] that the tree is stressed.

Example: I hear water running in the house.

It's downstairs because I am in the upstairs bathroom. No one else is up yet. I conclude a pipe has burst, or someone is using my water from the hose, or the burglar had to wash her hands.

Then I remember the power outage. Now the running water makes sense because the water softener is out of cycle and using water during the early day instead of the middle of the night.

Basic to interpretation [and thus to research] is inference-making. An inference is a conclusion or judgment which expresses some significant attitude suggested by what is seen, heard, or read. We see the sky clouding up and infer that rain is coming...

Sometimes a single observation may trigger a chain of inferences. Thus Robinson Crusoe saw a footprint and inferred (1) that somebody else was on the island, (2) that there was a possibility of danger from that person, (3) that he should take precautions against that danger. In all such instances the thing observed becomes a sign of something, and the inference interprets that sign. (MacCrimmon 25)