understanding implied volatility

Dear traderji , saint , ivanboesky & senior members I have following doubts in cash & futures arbitrage can you help me to solve them :



1) what do increase in implied volatility of calls imply & what do decrease in implied volatility of calls imply?

2) What do increase in implied volatility of puts imply & what do decrease in implied volatility of puts imply?

3) How does implied volatility acts as a sentiment indicator?

4) In what ways do changes in historical volatility affect implied volatility?


with regards,

learningcurve

Hey I been looking for info on the same (IV).will post wen I found relevant material.